Phytopigments are a marker of the amount of organic matter that settles in sediments. Phytopigment concentrations in deep-sea sediments collected world-wide showed a very strong right-skew. Of these two summary statistics, 0.015 and 0.009 grams per square meter of bottom surface, which one is the mean and which one is the median? Explain your reasoning.

According to a study by Nielsen Mobile, "Teenagers ages 13 to 17 are by far the most prolific texters, sending 1742 messages a month" Mr. Williams, a high school statistics teacher, was skeptical about the claims in the article. So he collected data from his first-period statistics class on the number of text messages they had sent over the past 24 hours. Here are the data:

$$\begin{array}{rrrrrrrrrrrr} \hline 0 & 7 & 1 & 29 & 25 & 8 & 5 & 1 & 25 & 98 & 9 & 0 & 26 \\ 8 & 118 & 72 & 0 & 92 & 52 & 14 & 3 & 3 & 44 & 5 & 42 & \\ \hline \end{array}$$

Sunny was the student who sent 42 text messages. What is Sunny's percentile?

Determine whether the hypothesis test involves a sampling distribution of means that is a normal distribution, Student t distribution, or neither:

Claim about IQ scores of statistics instructors: $\mu>100$. Sample data: $n=15$, $\bar{x}=118, s=11$. The sample data appear to come from a normally distributed population with unknown $\mu$ and $\sigma$.

Obesity is defined as having a Body Mass Index (BMI = 30 grams/kilogram2) over 30. A statistics practitioner took a random sample of American adults and classified their BMI as either 1. Under 20, 2. 20–30, 3. Over 30. There are 234,564,000 American adults. Estimate with 95% confidence the number of Americans who are obese.

Most of the following sentences contain pronouns that do not agree with their antecedents. Identify and correct each pronoun that does not agree with its antecedent. If a sentence is already correct, write $C$.

EXAMPLE: A number of students here plan to make computer animation his or her career. his or her-their

Be sure to review the statistics; it revealed some interesting trends.

In paragraph 7, the author lists the known quantities of satellites for Jupiter and Saturn with the purpose of A. increasing the likelihood that the new planets' will have satellites. B. impressing the audience with statistics. C. describing how Jupiter and Saturn are unlike the discovered planets. D. providing an example that supports the new planets' having satellites. E. emphasizing the argument for space exploration.

Choose the letter of the correct term or concept below to complete the sentence. a. variance b. sample c. longitudinal study d. control group e. single-blind experiment f. double-blind experiment g. placebo effect h. statistics i. normal j. frequency distribution. Measures of __________ indicate how spread out the scores of a distribution are.

Modeling Data The table shows the Consumer Price Index (CPI) for selected years. (Source: Bureau of Labor Statistics)

Use a graphing utility to plot the data and graph the model. Compare the data with the model.

Here are the annual numbers of deaths from tornadoes in the United States from 1995 through 2015:

30, 25, 67, 130, 94, 41, 40, 55, 54, 35, 38, 67, 81, 126, 21, 45, 553, 70, 55, 47, 36

Find these statistics:

a) mean

b) median and quartiles

c) range and IQR

Use the following data set. The data represent the heights (in inches) of students in a statistics class.

$$\begin{array}{llllllllll}52 & 54 & 55 & 56 & 56 & 56 & 58 & 59 & 60 & 61 \\ 61 & 63 & 65 & 67 & 68 & 68 & 70 & 71 & 72 & \end{array}$$

Find the height that corresponds to the first quartile.

Perform each of the following steps.

a. State the hypotheses and identify the claim. b. Find the critical value(s). c. Find the test value. d. Make the decision. e. Summarize the results.

Use the traditional method of hypothesis testing unless otherwise specified.

According to the Bureau of Transportation Statistics, on-time performance by airlines is described as follows:

Records of 200 randomly selected flights for a major airline company showed that 125 planes were on time; 40 were delayed because of weather, 10 because of a National Aviation System delay, and the rest because of arriving late. At $\alpha=0.05$, do these results differ from the government's statistics?

Suppose that X1,.............., Xn form a random sample from a distribution with the following p.d.f.:

$$(x \mid \beta, \theta)= \begin{cases}\beta e^{-\beta(x-\theta)} & \text { for } x \geq \theta \\ 0 & \text { otherwise }\end{cases}$$

where $\beta$ and $\theta$ are unknown $(\beta>0,-\infty<\theta<\infty)$. Determine a pair of jointly sufficient statistics.

The AP Statistics exam was first given in 1997. The following data show the growth in the number of AP Statistics exams from 1997 (Year 1) to 2014 (Year 18).

$$\begin{array}{|l|c|c|c|c|c|c|} \hline \text { Year } & 1 & 2 & 3 & 4 & 5 & 6 \\ \hline \text { Exams } & 7667 & 15,486 & 25,240 & 34,118 & 40,259 & 49,824 \\ \hline \text { Year } & 7 & 8 & 9 & 10 & 11 & 12 \\ \hline \text { Exams } & 58,230 & 65,878 & 76,786 & 88,237 & 98,033 & 108,284 \\ \hline \text { Year } & 13 & 14 & 15 & 16 & 17 & 18 \\ \hline \text { Exams } & 116,876 & 129,899 & 142,910 & 153,589 & 169,508 & 184,752 \\ \hline \end{array}$$

Calculate a quadratic model for these data.

The index of deflated turnover for retail trade reveals the activity in volume of the retail trade sector. The United Nations Statistics Division reports Retail trade deflated sales/turnover (seasonally adjusted) with $2005=100$. The data file holds this index for 43 countries for the years 2007-2010.

c) Test an appropriate hypothesis to find if the association is significant.