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STAT 301 Exam 1

Terms in this set (28)

Does the average time gray squirrels in Indiana manipulate a nut with their paws depend on the type of nut? Squirrels turn nuts around in their paws to assess integrity, weight, and shape, until the nut is eaten or stored. Researchers selected a sample of gray squirrels from the state of Indiana by selecting at random 20 parks and then randomly catching five squirrels in each selected park. Oak nuts were provided to fifty randomly selected squirrels from the sample. The rest of the squirrels were given hickory nuts. Researchers recorded the time each squirrel manipulated the nut before eating or storing it.
Which experimental design was used in this study?

a. Randomized Block
b. Completely Randomized
c. Multistage Random
d. Stratified Random
e. Matched Pairs
Completely Randomized
Does the average time gray squirrels in Indiana manipulate a nut with their paws depend on the type of nut? Squirrels turn nuts around in their paws to assess integrity, weight, and shape, until the nut is eaten or stored. Researchers selected a sample of gray squirrels from the state of Indiana by selecting at random 20 parks and then randomly catching five squirrels in each selected park. Oak nuts were provided to fifty randomly selected squirrels from the sample. The rest of the squirrels were given hickory nuts. Researchers recorded the time each squirrel manipulated the nut before eating or storing it.
Which sampling design was used in this study?

a. Randomized Block
b. Completely Randomized
c. Multistage Random
d. Stratified Random
e. Matched Pairs
Stratified Random
Does the average time gray squirrels in Indiana manipulate a nut with their paws depend on the type of nut? Squirrels turn nuts around in their paws to assess integrity, weight, and shape, until the nut is eaten or stored. Researchers selected a sample of gray squirrels from the state of Indiana by selecting at random 20 parks and then randomly catching five squirrels in each selected park. Oak nuts were provided to fifty randomly selected squirrels from the sample. The rest of the squirrels were given hickory nuts. Researchers recorded the time each squirrel manipulated the nut before eating or storing it.
What is the population of this study?

a. All gray squirrels in Indiana
b. All oak and hickory nuts
c. All squirrels
d. All times a gray squirrel in Indiana eats or catches a nut
All gray squirrels in Indiana
Does the average time gray squirrels in Indiana manipulate a nut with their paws depend on the type of nut? Squirrels turn nuts around in their paws to assess integrity, weight, and shape, until the nut is eaten or stored. Researchers selected a sample of gray squirrels from the state of Indiana by selecting at random 20 parks and then randomly catching five squirrels in each selected park. Oak nuts were provided to fifty randomly selected squirrels from the sample. The rest of the squirrels were given hickory nuts. Researchers recorded the time each squirrel manipulated the nut before eating or storing it.
Fourteen of the squirrels in the sample ran away and hid from the researchers while manipulating the nut. No data was collected from those squirrels. What sort of bias might this introduce?

a. No bias
b. Undercoverage
c. Response bias
d. Non-response bias
Non-response bias
Does the average time gray squirrels in Indiana manipulate a nut with their paws depend on the type of nut? Squirrels turn nuts around in their paws to assess integrity, weight, and shape, until the nut is eaten or stored. Researchers selected a sample of gray squirrels from the state of Indiana by selecting at random 20 parks and then randomly catching five squirrels in each selected park. Oak nuts were provided to fifty randomly selected squirrels from the sample. The rest of the squirrels were given hickory nuts. Researchers recorded the time each squirrel manipulated the nut before eating or storing it.
Half the experiment (squirrels provided with oak nuts) was conducted in the Summer and the other half (squirrels provided with hickory nuts) in the Fall. The time a squirrel manipulates a nut might be affected by whether food is abundant or scarce. Food preferred by squirrels is more abundant in the Fall than in the Summer. Choose the correct statement.

a. The time of the year at which the experiment is conducted is a lurking variable.
b. That oversight decreases the variability of the results.
c. Sampling bias will affect this experiment because of the two different seasons, since the two seasons were not chosen randomly.
d. That oversight results in undercoverage bias.
The time of the year at which the experiment is conducted is a lurking variable.
Does the average time gray squirrels in Indiana manipulate a nut with their paws depend on the type of nut? Squirrels turn nuts around in their paws to assess integrity, weight, and shape, until the nut is eaten or stored. Researchers selected a sample of gray squirrels from the state of Indiana by selecting at random 20 parks and then randomly catching five squirrels in each selected park. Oak nuts were provided to fifty randomly selected squirrels from the sample. The rest of the squirrels were given hickory nuts. Researchers recorded the time each squirrel manipulated the nut before eating or storing it.
Which statement is correct?
a. Researchers needed approval by a review board before conducting this study.
b. Researchers should not publish the location where the experiment was conducted to follow the confidentiality principle.
c. Researchers should have repeated the experiment to follow the replication/repeat principle.
Researchers needed approval by a review board before conducting this study.
See graph 1.
Which of the following statements is correct?

a. The median is most likely a value greater than 3175.12.
b. The distribution of the variable "Birth_wt" is skewed right.
c. The value of the variance can be calculated as (4000.00-1500.00)=2500.00.
The median is most likely a value greater than 3175.12.
See graph 1
The values of birth weight in grams in the US ("Birth_wt") presented in the graph above were collected from a sample of newborns at a hospital in Indianapolis. A recent publication includes data on birth weight compiled from a sample of 120 newborns at a hospital in Denver. Which of the following statements is true?

a. It is expected that the mean birth weight calculated from the data collected in Denver is not exactly 3175.12 due to sampling variability.
b. It is expected that the mean birth weight for the entire population of newborns is exactly the average of the Indianapolis and Denver means.
c. It is expected that the mean birth weight calculated from the data collected in Denver is not exactly 3175.12 due to sample bias.
It is expected that the mean birth weight calculated from the data collected in Denver is not exactly 3175.12 due to sampling variability.
Let X be the variable corresponding to the weight at birth (in pounds) of a newborn in the US. For the population of newborns in the US, X is distributed as N(7.3,1.1).
Consider the question, what is the probability that the weight at birth of a single newborn is less than 7.1 pounds? Indicate which probability statement corresponds to this question.

a. P (Xbar < 7.1)
b. P (X < 7.1)
c. P(Xbar > 7.1)
d. P (X > 7.1)
b. P (X < 7.1)
Let X be the variable corresponding to the weight at birth (in pounds) of a newborn in the US. For the population of newborns in the US, X is distributed as N(7.3,1.1).
Calculate the z-score ( zo ) for X = xo where xo = 6.0. Enter your final answer rounded to two decimal places.
-1.18
Let X be the variable corresponding to the weight at birth (in pounds) of a newborn in the US. For the population of newborns in the US, X is distributed as N(7.3,1.1).
For the situation in the previous question, is the following statement true or false?
P( X > xo ) = P( Z > zo )

a. True
b. False
True
See graph 2
The density curve below represents the Standard Normal density curve.
The variable zo = -1.38 is shown in the picture. (NOTE: this may be different than the number calculated above). Each numbered box in the picture corresponds to a blank below. Fill in each blank below, as indicated, with the requested information about the picture. Reference tables are provided at the end of the exam if needed.
______ 1. Value at the center of the distribution (written with no decimals)
_______2. Probability corresponding to the shaded region (written to 4 decimals)
________ 3. Probability corresponding to the un-shaded region (written to 4 decimals)
0, 0.0830, 0.9162
Let X be the variable corresponding to the weight at birth (in pounds) of a newborn in the US. For the population of newborns in the US, X is distributed as N(7.3, 1.1). A sample of size "n" newborns was selected from a hospital in Indianapolis to be part of a research study. The mean weight at birth of the newborns in this sample was calculated.
The value of the mean of the sampling distribution of X bar is equal to:

a. x bar
b. μ
c. We do not have enough information to determine it.
μ
Let X be the variable corresponding to the weight at birth (in pounds) of a newborn in the US. For the population of newborns in the US, X is distributed as N(7.3, 1.1). A sample of size "n" newborns was selected from a hospital in Indianapolis to be part of a research study. The mean weight at birth of the newborns in this sample was calculated.
The value of the standard deviation of the sampling distribution of X bar is equal to:

a. We do not have enough information to determine it.
b. σ
c. σ/√n
σ/√n
Let X be the variable corresponding to the weight at birth (in pounds) of a newborn in the US. For the population of newborns in the US, X is distributed as N(7.3, 1.1). A sample of size "n" newborns was selected from a hospital in Indianapolis to be part of a research study. The mean weight at birth of the newborns in this sample was calculated.
Consider the question, what is the probability that the mean weight at birth of "n" newborns in the US is more than 7.6 pounds? Indicate which probability statement corresponds to this question.

a. P(X bar > 7.6)
b. P(X > 7.6)
c. P(X < 7.6)
d. P(X bar < 7.6)
P(X bar > 7.6)
Let X be the variable corresponding to the weight at birth (in pounds) of a newborn in the US. For the population of newborns in the US, X is distributed as N(7.3, 1.1). A sample of size "n" newborns was selected from a hospital in Indianapolis to be part of a research study. The mean weight at birth of the newborns in this sample was calculated.
The sample selected from the Indianapolis hospital had 95 newborns. Calculate the z-score for x bar = 7.54 pounds. Enter the value rounded to 2 decimals.
2.13
Let X be the variable corresponding to the weight at birth (in pounds) of a newborn in the US. For the population of newborns in the US, X is distributed as N(7.3, 1.1). A sample of size "n" newborns was selected from a hospital in Indianapolis to be part of a research study. The mean weight at birth of the newborns in this sample was calculated.
Determine if the following statement is true or false based on the sample size, measured sample mean, and rounded z-score from the previous question.
True or False: The probability that another random sample of the same size would have a mean birth weight greater than the measured mean is less than 0.03.

a. True
b. False
True
Below are the weights at birth (in pounds) of twelve newborns in the US.
5.2 5.5 5.8 6.1 6.8 6.9 7.0 7.1 7.3 7.3 7.5 7.8
Calculate the mean of this data and enter the value rounded to 2 decimals.
6.69
Below are the weights at birth (in pounds) of twelve newborns in the US.
5.2 5.5 5.8 6.1 6.8 6.9 7.0 7.1 7.3 7.3 7.5 7.8
Calculate the median of this data and enter the value with 2 decimals.
6.95
Below are the weights at birth (in pounds) of twelve newborns in the US.
5.2 5.5 5.8 6.1 6.8 6.9 7.0 7.1 7.3 7.3 7.5 7.8
Calculate the value below which a number from the data set is considered a low outlier. Enter the value rounded to 1 decimal.
3.9
True or False: A number in a data set is a low outlier if its value is larger than Q1.

a. True
b. False
False
True or False: The mean of a data set is one of the values included in the five-number summary.

a. True
b. False
False
See graph 3
1.mean
2.median
3.mode
4.first quartile
5.third quartile
6.interquartile range
7.high outlier
8.low outlier
9.maximum
10.minimum
______ C
______ E
______ A
______ D
______ B
2, 10, 9, 4, 5
See graph 3
Based on the boxplot above, which of the following statements is true?

a. The weights at birth in this data set follow a right skewed distribution.
b. The weights at birth in this data set follow a symmetric distribution.
c. The weights at birth in this data set follow a left skewed distribution.
The weights at birth in this data set follow a left skewed distribution.
Match each scenario on the left with an option on the right that best describes it. Each answer option may be used once, more than once, or not at all. You may need to scroll down slightly to find the answer options listed on the right. See paper #4
___________ Twenty truck drivers answered a flier to test drive the latest model of a truck and provided feedback.

___________ What is the mean weight at birth of newborns in the US? A sample of 500 newborns was selected by randomly choosing ten newborns among all the newborns born in each of the 50 states.

__________ What is the mean weight at birth of newborns in the US? A sample of 500 newborns was selected as follows. First, ten states were randomly selected. Next, five hospitals were randomly selected in each of those ten states. Finally, ten newborns were randomly selected in each of those hospitals.

__________ Two drugs were recently developed to increase blood pressure. Twenty patients with low blood pressure participated in a study aimed at comparing the efficiency of both drugs. The participants were first divided in two age groups (20 to 40 and older than 40). Half the participants in each age group were assigned at random to take one of the drugs for a month, whereas the other half took the other drug also for a month.

_________ A group of 20 truck drivers were asked to test drive the latest models of two trucks. Each of the 20 drivers drove one of the truck models for an hour. After a two hour break the drivers were asked to drive the other truck model also for an hour. All 20 drivers provided numerical feedback to several questions pertaining to both truck models.

________ A sign was posted at pediatrician offices across the US inviting parents/guardians of newborn children to participate in a research study.

_________ Two drugs were recently developed to increase blood pressure. Twenty patients with low blood pressure were randomly selected to participate in a study aimed at comparing the efficiency of both drugs.

___________ Two drugs were recently developed to increase blood pressure. Twenty patients with low blood pressure participated in a study aimed at comparing the efficiency of both drugs. Ten participants were randomly assigned to take one of the drugs for a month. The other ten participants took the other drug also for a month.
4, 2, 3, 6, 7, 4, 1, 5
See graph 5
Which of the following statements is correct?
a. No questions can be answered regarding the area under the density curve because it is not symmetric.
b. The total area under the density curve is one.
c. The area under the density curve to the left of X=2 is 0.5.
d. The area under the density curve to the left of X=2 is the same as the area under the density curve to the right of X=2.
The total area under the density curve is one.
See graph 5
Which of the following statements is correct?
a. We can conclude that the percentage of values of X above 8 has to be less than 30%, if the percentage of values of X below 6 is 70%,
b. The values of X that appear more often are those above 7.
c. The percentage of values of X below the mode is the same as the percentage of values of X above the mode.
We can conclude that the percentage of values of X above 8 has to be less than 30%, if the percentage of values of X below 6 is 70%
Match each scenario on the left with a graph option on the right that best describes it. Each answer choice may be used once, more than once, or not at all. See paper #6

______ I want to see the distribution of majors of the students in my STAT 301 section.

_____ Peter, a local realtor, wants to compare the distribution of prices of houses sold in West Lafayette with that of prices of houses sold in Lafayette, in the past year.

_____ Anna wants to visualize the distribution of type of books (children, fiction, history, religious studies, biographies, other) in the public library.
1, 3, 1
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