stats test 2

A study of king penguins looked for a relationship between how deep the penguins dive to seek food and how long they stay underwater. For all but the shallowest dives, there is a linear relationship that is different for different penguins. The study report gives a scatterplot for one penguin titled " The relation of dive duration (DD) to depth (D)." Duration DD is measured in minutes and depth D is in meters. The report then says, " The regression equation for this bird is: DD = 2.68 + 0.0041 D. (a) What is the slope of the regression line?. ANSWER minutes per meter.

0.0041 minutes per meter.

A study of king penguins looked for a relationship between how deep the penguins dive to seek food and how long they stay underwater. For all but the shallowest dives, there is a linear relationship that is different for different penguins. The study report gives a scatterplot for one penguin titled " The relation of dive duration (DD) to depth (D)." Duration DD is measured in minutes and depth D is in meters. The report then says, " The regression equation for this bird is: DD = 2.68 + 0.0041 D.

3.8075 minutes.

The length of human pregnancies from conception to birth varies according to a distribution that is approximately Normal with mean 266 days and standard deviation 16 days. According to the empirical rule, approximately 95% of all pregnancies last between A. 234 and 298 days. B. 218 and 314 days. C. 260 and 320 days. D. 250 and 282 days. E. None of the above.

A. 234 and 298 days.

a) To completely specify the shape of a Normal distribution, you must give A. the mean and the standard deviation. B. the variance and the standard deviation. C. the mean and the median. D. the five-number summary. E. All of the above.

A. the mean and the standard deviation.

A dataset shows that, on average, smokers do not live as long as nonsmokers and heavy smokers do not live as long as light smokers. If you compute the least squares line for y = AGE at time of death and x = NUMBER of packets per day typically smoked, then the slope of your regression line A. will be less than zero. B. will be greater than zero. C. must be between -1 and 1. D. will be exactly zero.

A. will be less than zero.

The points on a scatterplot lie close to the line whose equation is y=6x−5. The slope of the line is A. 5 B. 6 C. -6 D. 11 E. None of the above.

B. 6

A study was performed to examine the personal goals of children in elementary school. A random sample of students was selected and the sample was given a questionnaire regarding achieving personal goals. They were asked what they would most like to do at school: make good grades, be good at sports, or be popular. Each student's sex (boy or girl) was also recorded. If a contingency table for the data is evaluated with a chi-squared test, what are the hypotheses being tested? A. The null hypothesis that there is no relationship between personal goals and sex vs. the alternative hypothesis that there is a positive, linear relationship. B. The null hypothesis that sex and personal goals are not related vs. the alternative hypothesis that sex and personal goals are related. C. The null hypothesis that the mean personal goal is the same for boys and girls vs. the alternative hypothesis is that the means differ. D. The null hypothesis that boys are more likely than girls to desire good grades vs. the alternative that girls are more likely than boys to desire good grades. E. None of the above.

B. The null hypothesis that sex and personal goals are not related vs. the alternative hypothesis that sex and personal goals are related.

The variables considered in a chi-squared test used to evaluate a contingency table A. have rounding errors. B. can be averaged. C. are categorical. D. are normally distributed. E. have small standard deviations.

C. are categorical.

he scores of adults on an IQ test is approximately Normal with mean 100 and standard deviation 15. Corinne scores 118 on such test. Her z-score is about A. 0.67 B. 7.87 C. 18 D. 1.2 E. None of the above.

D. 1.2

Fred keeps his savings in his mattress. He began with $550 from his mother and adds $175 each year. His total savings y after x years are given by the equation A. y=175+550x B. y=175+x C. y=550−175x D. y=550+175x E. None of the above.

D. y=550+175x

A χ2 statistic provides strong evidence in favor of the alternative hypothesis if its value is A. a large negative number. B. close to 1. C. exactly 1.96 D. close to 0. E. a large positive number.

E. a large positive number.