The following table shows the average life span for some mammals in years, according to infoplease. com. Graph these average life spans and describe the distribution. What is a typical life span? Identify the three outliers and report their life spans. If you were to include humans in this graph, where would the data point be? Humans live an average of about $75$ years.

Animal	Gestation (days)	Life span (years)
Baboon	187	12
Bear, grizzly	225	25
Beaver	105	25
Bison	285	15
Camel	406	12
Cat, domestic	63	12
Chimp	230	20
Cow	284	15
Deer	201	8
Dog, domestic	61	12
Elephant, African	660	35
Elephant, Asian	645	40
Elk	250	16
Fox, red	52	7
Giraffe	457	10
Goat	151	8
Gorilla	258	20
Hippo	238	41
Horse	330	20
Leopard	98	12
Lion	100	15
Monkey, rhesus	166	15
Moose	240	12
Pig, domestic	112	10
Puma	90	12
Rhino, black	450	15
Sea Lion	350	12
Sheep	154	12
Squirrel, gray	44	10
Tiger	105	16
Wolf, maned	63	5
Zebra, Grant's	365	15

The table shows prices of 50 college textbooks in a community college bookstore, rounded to the nearest dollar. Make an appropriate graph of the distribution of the data, pose a statistical question and describe the distribution.

The following table shows the first few entries for the number of hours of sleep in one night for a sample of college students. The data are stacked and coded, where $0$ represents a male student and $1$ represents a female student. What would be appropriate graphs to compare the distributions of hours of sleep in one night for male and female college students if you had the complete data set? Explain. Write a statistical question that can be answered with the complete data.

Suppose a group of school-aged children is asked, “Which of these three ice cream flavors do you like the most: vanilla, chocolate, or strawberry?” Describe a bar graph of their responses that would have the least amount of variability. Also describe a bar graph that would have the most variability.

The data show monthly rents for studio and one-bedroom apartments in San Francisco. Write a statistical question appropriate for these data and a brief comparison of the distribution of rents for these two types of housing units. Include appropriate graphics. (Source: Zillow)

Studio Apartments

One Bed-room Apartments

How, in general, do unemployment rates vary by race and ethnicity, gender, occupation, and education? Why does the average length of time people are unemployed rise during a recession?

In 2017 a pollution index was calculated for a sample of cities in the western states using data on air and water pollution. Assume the distribution of pollution indices is unimodal and symmetric. The mean of the distribution was 43.0 points with a standard deviation of 11.3 points.

a. What percentage of western cities would you expect to have a pollution index between 31.7 and 54.3 points?

b. What percentage of western cities would you expect to have a pollution index between 20.4 and 65.6?

c. The pollution index for San Jose in 2017 was 51.9 points. Based on this distribution, was this unusually high? Explain.

An article in the Journal of the Academy of Nutrition and Dietetics reported on a study of diet in subjects with moderate to severe acne. Read the excerpts from the abstract and answer the questions that follow.

Methods: Sixty-four participants (no acne, n = 32; moderate/severe acne, n = 32) were included in this study. Participants completed a 5-day food record, had blood drawn and completed a questionnaire to evaluate food-aggravated acne beliefs and acne-specific quality of life. Results: Participants with moderate/severe acne consumed greater total carbohydrate compared to participants without acne. Participants with moderate/severe acne had greater insulin compared to participants without acne. Although there were no differences between groups, 61% of participants reported food-influenced acne.

a. Was this a controlled experiment or an observational study? Explain how you know.

b. Assuming the study was properly conducted, can we conclude that higher consumption of carbohydrates causes more severe acne? Explain.

The distribution of in-state annual tuition for all colleges and universities in the United States is bimodal. What is one possible reason for this bimodality?

Indicate which variable you think should be the predictor (x) and which variable should be the response (y). Explain your choices.

a. A researcher measures subjects’ stress levels and blood pressures.

b. Workers who commute by car record the length of their commutes (in miles) and the amount spent monthly on gasoline purchases.

c. Amusement parks record the heights and maximum speeds of roller coasters.

The Harvard Heart Letter reported on a study that examined the diets of $1226$ older women over $15$ years. They discovered that the more vegetables the women consumed, the lower their risk of dying of cardiovascular disease. From this study can we conclude that eating a diet high in vegetables prevents cardiovascular disease? Why or why not?

Distributions of gestation periods (lengths of pregnancy) for humans are roughly bell-shaped. The mean gestation period for humans is 272 days, and the standard deviation is 9 days for women who go into spontaneous labor. Which is more unusual, a baby being born 9 days early or a baby being born 9 days late? Explain.

Suppose college women’s heights are approximately Normally distributed with a mean of 65 inches and a population standard deviation of 2.5 inches. What height is at the 20th percentile? Include an appropriately labeled sketch of the Normal curve to support your answer.

Applicants to California community colleges are asked to indicate one of these education goals at the time of application: transfer to a four-year institution, an AA degree, a CTE certificate, job retraining, or personal enrichment. In a group of 500 applications, describe a bar graph of these data that would have the least amount of variability. Also describe a bar graph that would have the most variability.