Instructions

MATCH ANSWERS WITH CORRESPONDING QUESTIONS

Please review all problems. Unless otherwise noted, each problem is worth 5 points. To obtain full credit, you must use the methods specified in the course text.Please, format your work as explained in chapter 2 of the Frequently Asked Questions (FAQ) document. When doing calculations, such as the variance, standard deviation, or the correlation coefficient, use technology wherever possible. There is no need to do calculations by hand unless I direct you to do so.

Rounding.You should round your z-scores totwodecimal places when using a normal distribution table and the areas under the normal curve todecimal places. When using the t-distribution or doing other calculations, round to 3 decimal places unless otherwise directed. Never round until the last step of your calculations (Note: see FAQ 4.2).

Problems

Income (thousands of dollars)
38	39	50	49	36	43	45	38	42	42
49	45	24	52	53	30	71	35	35	38

Problem 1.Using Table 1, answer the following questions. The data set represents the incomes (in thousands of dollars) of a sample of 20 employees at a company.

a. Find the range, mean, median, and mode of the data set.

• Range:
• Mean:
• Median:
• Mode:

b. Construct a frequency distribution for the data set using 5 classes. Include the midpoints, frequency, and relative frequency.Fill in Table 2.

Class	Tally	Frequency	Midpoint	Relative Frequency

c. Make a relative frequency histogram.Use graph paper and use the frequency distribution created in part b. Which class has the greatest relative frequency and which has the least relative frequency (Record your answers in Table 3.)?

Least Relative Frequency	Greatest Relative Frequency

2. Use Table 4 to answer the questions.The table shows the results of a survey in which men and women workers ages 25 to 64 were asked if they have at least one month's income set aside for emergencies.

	Men	Women	Total
Less than one month's income	89	72	161
One month's income or more	96	87	183
Total	185	159	344

a.Find the probability that a randomly selected worker has one month's income or more set aside for emergencies.

b.Given that a randomly selected worker is a male, find the probability that a worker has less than one month's income set aside for emergencies.

c.Given that a randomly selected worker has one month's income or more set aside for emergencies, find the probability that the worker is a female.

d.Are the events "having less than one month's income saved" and "being male" independent or dependent? Explain.

3. Use the following information for problems 3a-3c.The percentage distribution of the number of occupants in vehicles traveling down a highway is shown in the pie chart (see Figure 1). (source: Washington State Department of Transportation.)

Figure 1. Pie Chart: The percentage distribution of the number of occupants in vehicles traveling down a highway

Find each probability.

3a.The probability of randomly selecting a car with two occupants.

3b.The probability of randomly selecting a car with two or more occupants.

3c.The probability of randomly selecting a car with between two and five occupants, inclusive.

4. Scores.Scores for a qualification exam are normally distributed, with a mean of 80 and a standard deviation of 10. To be qualified for an interview, you must score in the top 10%. What is the lowest score you can earn and still be qualified for an interview?

5. Coffee temperatures.You randomly select 25 coffee shops and measure the temperature of coffee sold at each. The sample mean temperature is one-hundred sixty-two degrees F with a sample standard deviation of 8.0 degrees F. Find the 95% confidence interval for the mean temperature. Assume the temperatures are approximately normally distributed.