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Sleep Mean As part of the National Health and Nutrition Examination Survey, subjects were asked how long they slept the preceding night, and the following times (hours) were reported: 8, 7, 5, 7, 4, 7, 6, 7, 8, 8, 8, 6. Find the mean.

Average The defunct website IncomeTaxList.com listed the 鈥渁verage鈥� annual income for Florida as $35,031. What is the role of the term average in statistics? Should another term be used in place of average?

Arsenic in Rice Listed below are measured amounts (mg per serving) of arsenic in a sample of servings of brown rice [data from the Food and Drug Administration (FDA)]. Construct a frequency distribution. Use a class width of 2 mg, and use 0 mg as the lower class limit of the first class.

6.1 5.4 6.9 4.9 6.6 6.3 6.7 8.2 7.8 1.5 5.4 7.3

Range Rule of Thumb for Estimating s The 20 brain volumes (cm3 ) from Data Set 8 鈥淚Q and Brain Size鈥� in Appendix B vary from a low of 963 cm3 to a high of 1439 cm3. Use the range rule of thumb to estimate the standard deviation s and compare the result to the exact standard deviation of 124.9 cm3.

Old Faithful Geyser Listed below are prediction errors (minutes) that are differences between actual eruption times and predicted eruption times. Positive numbers correspond to eruptions that occurred later than predicted, and negative numbers correspond to eruptions that occurred before they were predicted. (The data are from Data Set 23 鈥淥ld Faithful鈥� in Appendix B.) Find the (a) mean; (b) median; (c) mode; (d) midrange; (e) range; (f) standard deviation; (g) variance; (h) Q1; (i) Q3.

4 -7 0 1 -1 1 -4 -7 22 7 -5 1

z Scores LeBron James, one of the most successful basketball players of all time, has a height of 6 feet 8 inches, or 203 cm. Based on statistics from Data Set 1 鈥淏ody Data鈥� in Appendix B, his height converts to the z score of 4.07. How many standard deviations is his height above the mean?

In Exercises 9 鈥�12, consider a value to be significantly low if its z score is less than or equal to -2 or consider the value to be significantly high if its z score is greater than or equal to 2.

MCAT In a recent year, scores on the Medical College Admission Test (MCAT) had a mean of 25.2 and a standard deviation of 6.4. Identify the MCAT scores that are significantly low or significantly high.

Critical Thinking. For Exercises 5鈥�20, watch out for these little buggers. Each of these exercises involves some feature that is somewhat tricky. Find the (a) mean, (b) median, (c) mode, (d) midrange, and then answer the given question.

Peas in a Pod Biologists conducted experiments to determine whether a deficiency of carbon dioxide in the soil affects the phenotypes of peas. Listed below are the phenotype codes, where 1 = smooth-yellow, 2 = smooth-green, 3 = wrinkled-yellow, and 4 = wrinkled-green. Can the measures of center be obtained for these values? Do the results make sense?

2 1 1 1 1 1 1 4 1 2 2 1 2 3 3 2 3 1 3 1 3 1 3 2 2

In Exercises 5鈥�20, find the range, variance, and standard deviation for the given sample data. Include appropriate units (such as 鈥渕inutes鈥�) in your results. (The same data were used in Section 3-1, where we found measures of center. Here we find measures of variation.) Then answer the given questions.

Peas in a Pod Biologists conducted experiments to determine whether a deficiency of carbon dioxide in the soil affects the phenotypes of peas. Listed below are the phenotype codes, where 1 = smooth-yellow, 2 = smooth-green, 3 = wrinkled yellow, and 4 = wrinkled-green. Can the measures of variation be obtained for these values? Do the results make sense?

2 1 1 1 1 1 1 4 1 2 2 1 2 3 3 2 3 1 3 1 3 1 3 2 2

Sleep Notation Consider a sample of sleep times taken from the population of all adults living in Alaska. Identify the symbols used for the sample mean, population mean, sample standard deviation, population standard deviation, sample variance, and the population variance.