Exam 6: Putting Statistics to Work

Find the mode(s)for the given sample data. -Last year, nine employees of an electronics company retired. Their ages at retirement are listed below. Find the mode(s). 55 56 61 67 58 54

State whether you would expect the data set to be normally distributed. -Sales of birthday cards over a one-year period

Solve the problem. -The numbers below represent the amount of precipitation, in inches, on January 1st in eleven different U.S. cities. Find the mean precipitation. Round your answer to the nearest ten-thousandth Of an inch. 0.152 0.072 0.146 0.099 0.079 0.108 0.151 0.087 0.109 0.131 0.082

Use the 68-95-99.7 rule to solve the problem. -The amount of Jen's monthly phone bill is normally distributed with a mean of $61 and a standard deviation of $12. Fill in the blanks. $68 \%$ of her phone bills are between $\$$ and $\$$ ____

Obtain the five-number summary for the given data. -The weekly salaries (in dollars)of sixteen government workers are listed below. 690 599 813 644 728 576 481 618 529 679 685 465 559 787 498 826

Provide an appropriate response. -The area under the standard normal curve between 1 and 2 is equal to 0.1359. Scores on a particular aptitude test are normally distributed with a mean of 100 and a standard deviation of 10. Which of The following are equal to 13.59%? a. The percentage of scores between 120 and 130 b. The percentage of scores between 110 and 120 c. The percentage of scores between 80 and 90 d. The percentage of scores between 90 and 120

A hypothesis test is to be performed. State the null and alternative hypotheses. -Carter Motor Company claims that its new sedan, the Libra, will average better than 25 miles per gallon, which is the gas mileage of its competitor.

Use the range rule of thumb to approximate the standard deviation. -A distribution of data has a maximum value of 78, a median value of 51, and a minimum of 24. Round results to the nearest tenth.

Select the requested distribution. -Which of the distributions is multimodal?

State whether you think the difference between what occurred and what you would expect by chance is statisticallysignificant. -There are two candidates for mayor, Maria Hernandez, and Eric Wong. Of 100 people polled, 53 say they will vote for Maria Hernandez.

The result of a hypothesis is described in terms of the probability of obtaining a particular sample. Use the given contextto formulate the null and alternative hypotheses. Discuss whether the sample provides evidence for rejecting the nullhypothesis. -The mean resting heart rate for students at Northridge College is 72 beats per minute. An exercise physiologist believes that for athletes, the mean resting heart rate will be lower. She finds that for a random sample of 55 athletes at the college, the mean resting heart rate is 71 beats per minute. Assuming that the mean resting heart rate for all athletes at the college is 72 beats per minute, the probability of selecting a random sample with a mean of 71 or less beats per minute is $0.14$ .

Find the mode(s)for the given sample data. - $- 20 , - 45 , - 46 , - 45 , - 49 , - 45 , - 49$

Solve the problem. -Weights of adult females in a certain country are normally distributed with a mean of 137 lb and a standard deviation of 15 lb. A weight of 158 lb represents what percentile? Round the percentile to The nearest tenth.

Identify the distribution as symmetric, left-skewed, or right-skewed. -Lengths of human pregnancies

Provide an appropriate response. -Do you think it is possible to find two data sets such that the first data set has a smaller range but a larger standard deviation than the second set? If so, give an example of two such data sets. If it is not possible, explain why not.

Use the range rule of thumb to approximate the standard deviation. - $15,42,53,7,9,12,14,28,47$

Provide an appropriate response. -Which of the following statements is true?

State how many peaks you would expect for the distribution described. -Heights of a group of college athletes consisting of the gymnastics team and the basketball team

Find the margin of error for the survey results described. -In a survey of 602 employees of a large company, 25% said that they had high job satisfaction. Give your answer as a decimal to three decimal places.

Solve the problem. Round your answer to two decimal places. -Scores on a test are normally distributed with a mean of 86 and a standard deviation of 10. What is the standard score for an exam score of 79 ?