Chapter 2

q2)

Identify the lower class limits, upper class limits, class width, class midpoints, and class boundaries for the given frequency distribution. Also identify the number of individuals included in the summary.		Age (yr) when award was won	Frequency
	20-24	29
	25-29	32
	30-34	16
	35-39	4
	40-44	5
	45-49	2
	50-54	2

Identify the lower class limits.

(Type integers or decimals. Do not round. Use ascending order.)

5). Among fatal plane crashes that occurred during the past 70years, 619 were due to pilot error, 66 were due to other human error, 415 were due to weather, 563 were due to mechanical problems, and 531 were due to sabotage.

Construct the relative frequency distribution. What is the most serious threat to aviation safety, and can anything be done about it?

Complete the relative frequency distribution below.

Cause	Relative Frequency
Pilot error
Other human error	enter your response here%
Weather	enter your response here%
Mechanical problems	enter your response here%
Sabotage	enter your response here%

(Round to one decimal place as needed.)

Chapter 3

1. Find the (a) mean, (b) median, (c) mode, and (d) midrange for the data, and then (e) answer the given question. Listed below are foot lengths in inches of randomly selected women in a study of a country's military in 1988. Are the statistics representative of the current population of all women in that country's military?

9.98.68.88.69.49.69.09.29.88.88.8

2. Listed below are the annual tuition amounts of the 10 most expensive colleges in a country for a recent year. What does this "Top 10" list tell us about the population of all of that country's college tuitions?

$54,306$52,334$50,781$52,275$52,701

$54,306$53,288 $52,384 $53,616 $52,573

Find the mean, midrange, median, and mode of the data set.

3. One common system for computing a grade point average (GPA) assigns 4 points to an A, 3 points to a B, 2 points to a C, 1 point to a D, and 0 points to an F. What is the GPA of a student who gets an A in a 3-credit course, a B in each of three 2-credit courses, a C in a 3-credit course, and a D in a 4-credit course?

The mean grade-point score is

(Round to the nearest tenth as needed.)

4. A student's course grade is based on one midterm that counts as 5%of his final grade, one class project that counts as 5% of his final grade, a set of homework assignments that counts as 35% of his final grade, and a final exam that counts as 55% of his final grade. His midterm score is 81, his project score is 96, his homework score is 79, and his final exam score is 78. What is his overall final score? What letter grade did he earn (A, B, C, D, or F)? Assume that a mean of 90 or above is an A, a mean of at least 80 but less than 90 is a B, and so on.

His overall final score is?

5. The measure of center that is the value that occurs with the greatest frequency is the?

median

midrange

mode

mean

6- Listed below are the top 10 annual salaries (in millions of dollars) of TV personalities. Find the range, variance, and standard deviation for the sample data. Given that these are the top 10 salaries, do we know anything about the variation of salaries of TV personalities in general?

413937292120171312.611.9

7- If your score on your next statistics test is converted to a z score, which of these z scores would you prefer: 2.00, 1.00, 0, 1.00, 2.00? Why?

A.

The z score of 1.00 is most preferable because it is 1.00 standard deviation above the mean and would correspond to an above-average test score.

B.

The z score of 1.00 is most preferable because it is 1.00 standard deviation below the mean and would correspond to an above-average test score.

C.

The z score of 2.00 is most preferable because it is 2.00 standard deviations below the mean and would correspond to the highest of the five different possible test scores.

D.

The z score of 2.00 is most preferable because it is 2.00 standard deviations above the mean and would correspond to the highest of the five different possible test scores.

E.

The z score of 0 is most preferable because it corresponds to a test score equal to the mean.

8- Researchers measured the data speeds for a particular smartphone carrier at 50 airports. The highest speed measured was 74.5 Mbps. The complete list of 50 data speeds has a mean of x=18.14 Mbps and a standard deviation of s=20.13 Mbps.

a. What is the difference between the carrier's highest data speed and the mean of all 50 data speeds?

b. How many standard deviations is that [the difference found in part (a)]?

c. Convert the carrier's highest data speed to a z score.

d. If we consider data speeds that convert to z scores between 2 and 2 to be neither significantly low nor significantly high, is the carrier's highest data speed significant?

9) For a data set of the pulse rates for a sample of adult females, the lowest pulse rate is 32 beats per minute, the mean of the listed pulse rates is x=77.0 beats per minute, and their standard deviation is s=25.6 beats per minute.

a. What is the difference between the pulse rate of 32 beats per minute and the mean pulse rate of the females?

b. How many standard deviations is that [the difference found in part (a)]?

c. Convert the pulse rate of 32 beats per minute to a z score.

d. If we consider pulse rates that convert to z scores between 2 and 2 to be neither significantly low nor significantly high, is the pulse rate of 32 beats per minute significant?

10) Consider a value to be significantly low if its z score less than or equal to 2 or consider a value to be significantly high if its z score is greater than or equal to 2. A test is used to assess readiness for college. In a recent year, the mean test score was 21.6 and the standard deviation was 5.5. identify the test scores that are significantly low or significantly high.

What test scores are significantly low? Select the correct answer below and fill in the answer box(es) to complete your choice.

A.

Test scores that are less than enter your response here.

(Round to one decimal place as needed.)

B.

Test scores that are greater than enter your response here.

(Round to one decimal place as needed.)

C.

Test scores that are between enter your response here and

(Round to one decimal place as needed. Use ascending order.)

11) Use z scores to compare the given values. Based on sample data, newborn males have weights with a mean of 3266.4 g and a standard deviation of 577.1 g. Newborn females have weights with a mean of 3085.6 g and a standard deviation of 658.1g. Who has the weight that is more extreme relative to the group from which they came: a male who weighs 1700g or a female who weighs 1700g?

Since the z score for the male is z=?

and the z score for the female is z=?

the female or male has the weight that is more extreme.

(Round to two decimal places.)

12) Use z scores to compare the given values. In a recent awards ceremony, the age of the winner for best actor was 39 and the age of the winner for best actress was 57. For all best actors, the mean age is 47.5 years and the standard deviation is 7.3 years. For all best actresses, the mean age is 35.4 years and the standard deviation is 12.1 years. (All ages are determined at the time of the awards ceremony.) Relative to their genders, who had the more extreme age when winning the award, the actor or the actress? Explain.

Since the z score for the actor is z=(enter your response here) and the z score for the actress is z=(enter your response here), the

(actor or actress) had the more extreme age.

(Round to two decimal places.)

14) The following are the ratings of males by females in an experiment involving speed dating. Use the given data to construct a boxplot and identify the 5-number summary.

3.0

3.0

4.0

4.5

5.5

5.5

6.0

6.0

6.0

6.0

6.0

6.5

6.5

7.0

7.0

7.0

8.0

8.5

9.5

9.5

The 5-number summary is

(Use ascending order. Type integers or decimals. Do not round.)

15) Listed below are amounts of strontium-90 (in millibecquerels, or mBq) in a simple random sample of baby teeth obtained from residents in a region born after 1979. Use the given data to construct a boxplot and identify the 5-number summary.

127	129	132	136	139	143	146	147	150	151
153	153	155	156	157	164	166	167	170	177

The 5-number summary is

all in mBq.

(Use ascending order. Type integers or decimals. Do not round.)

16) In modified boxplots, a data value is a(n) _______ if it is above Q3+(1.5)(IQR) or below Q1(1.5)(IQR).

Outlier

z-score

quartile

whisker

17) When constructing a box plot, values are considered outliers if they are beyond which points?

Choose the correct answer below.

lower or upper fences

interquartile range

hinges

whiskers