# psy10

### 81 terms by iggles

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m2

sample

parameter

### The relationship between a statistic and a sample is the same as the relationship between

parameter and population

nominal

12

E(X- 4)2

### Although research questions usually concern a _____, the actual research is typically conducted with a _____.

population, sample

35

### What kind of frequency distribution graph is appropriate for scores measured on an interval or ratio scale?

either a histogram or a polygon

a bar graph

3

### For the following distribution, what is the highest score? X f 20-25 2 15-19 5 10-14 4 5-9 1

cannot be determined

7

11

3

U = 85

### A sample has a mean of M = 25. If one person with a score of X = 25 is added to the sample, what effect will it have on the sample mean?

The sample mean will remain the same

### One sample of n = 4 scores has a mean of M = 10, and a second sample of n = 8 scores has a mean of M = 20. If the two samples are combined, the mean for the combined sample will be

greater than 15 but less than 20

32/12 = 2.67

2.5

### A teacher gave a reading test to a class of 5th-grade students and computed the mean, median, and mode for the test scores. Which of the following statements cannot be an accurate description of the scores?

No one had a score exactly equal to the mode.

60/5 = 12

smaller than

### Which of the following samples would have the largest value for sample variance?

All the samples would have exactly the same variance.

### On an exam with a mean of average = 70, you have a score of X = 65. Which of the following values for the standard deviation would give you the highest position within the class?

standard deviantion = 0

1, 5, 8, 12, 22

+1.50

90

75

### A population with mean = 85 and stdev = 12 is transformed into z-scores. After the transformation, what are the values for the mean and standard deviation for the population of z-scores?

mean = 0 and stdev = 1

### Last week Tom had exams in Statistics and in English. He scored 10 points above the mean on both exams. From this information, what can you can conclude about the z-scores for Tom's two scores?

Both of Tom's z-scores are positive.

X = 64

### You have a score of X = 65 on an exam. Which set of parameters would give you the best grade on the exam?

mean = 60 and stdev = 5

47

75

4

### Which of the following is an advantage of transforming X values into z-scores

None of the other options is an advantage.

84.13%

0.1492

0.0919

69.15%

93.6

### A true/false test has 36 questions. Using the normal approximation to the binomial distribution, the probability of getting more than 25 correct by just guessing can be computed as

p(X greater than 25.5)

10/68

### For any normal distribution, what are the z-score values that form the boundaries for the middle 80%?

z = plus or minus1.28

### The distribution of sample means (for a specific sample size) consists of _____

the sample means for all the possible samples (for the specific sample size)

stdev M

### A random sample of n = 36 scores is selected from a population. Which of the following distributions definitely will be normal?

The distribution of sample means will form a normal distribution.

### When a random sample is selected from a population, the sample mean is not expected to be exactly equal to the population mean. On average, the size of the difference between a sample mean and the population mean is predicted by _____.

the standard error

4

10

z = 1.00

+1.0

10

24

0.1587

### A sample is obtained from a population with mean = 100 and stdev = 20. Which of the following samples would produce the z-score closest to zero?

a sample of n = 25 scores with M = 102

5

z = 1.00

p = 0.9938

test statistic

### The numerator of the z-score test statistic measures _____.

the actual distance between M and U(mean)

### Even if a treatment has no effect it is still possible to obtain an extreme sample mean that is very different from the population mean. If this happens, you are likely to _____.

reject H0 and make a Type I error.

### Which combination of factors will increase the chances of rejecting the null hypothesis?

a small standard error and a large alpha leve

### A researcher uses a hypothesis test to evaluate H0 mean = 80. Which combination of factors is most likely to result in rejecting the null hypothesis?

M = 90 and n = 20

### A researcher uses a hypothesis test to evaluate H0 mean = 80. If the researcher obtains a sample mean of M = 88, which combination of factors is most likely to result in rejecting the null hypothesis?

stdev = 5 and a = .05

### A researcher is predicting that a treatment will increase scores. If this treatment is evaluated using a directional hypothesis test, then the critical region for the test _____.

would be entirely in the right-hand tail of the distribution

0.30

### The power of a hypothesis test is defined as

the probability that the test will reject H0 if there is a real treatment effect.

n = 21

14

26

### One sample of n = 5 scores has a variance of s^2= 10 and a second sample of n = 10 scores has s^2= 20. If the pooled variance is computed for these two samples, then the value obtained will be _____.

closer to 20 than to 10

### One sample has a variance of s^2 = 20 and a second sample has a variance of s^2 = 30. If the two samples are the same size, what is pooled variance for the two samples?

somewhere between 20 and 30 but it is impossible to determine exactly where

### In an independent-measures hypothesis test, if t = 0, then _____.

the two sample means must be equal

2

### In general, if the variance of the difference scores increases, then the value of the t statistic will _____.

decrease (move toward 0 at the center of the distribution)

df = 19

### A repeated-measures study produces a sample mean difference of MD = 4.5 with s^2 = 100 for a sample of n = 16 participants. For this study, the estimated value of Cohen's d would be _____

d = 4.5/10 = 0.45

MD = 2

### A sample of difference scores has a mean of MD = 5. Which combination of factors is most likely to produce a significant difference?

n = 9 with a variance of s^2
= 36 for the difference scores

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