Inference Part 6 Flashcards
Which of the following is true about student’s t-models?
1) they are unimodal symmetric, and bell shaped
2) they have fatter tails than the normal distribution
3) as degrees of freedom increase, the t-models look more and more like the normal
1,2, and 3
A researcher found that a 98% confidence interval for the mean hours per week spent studying by college students was (13,17) which is true?
1) there is a 98% chance that the mean hours per week spent studying by college students is between 13 and 17 hours
2) 98% of college students study between 13 and 11 hours a week
3) students average between 13 and 17 hours per week an 98% of the weeks
None
A Professor was curious about her students gpa, she took a random sample of 15 students and found a mean gpa of 3.01 with a SD of 0.534. Which of the following formulas gives a 99% confidence interval for the mean gpa of the professors students?
3.01 +/- 2.977 (0.534/ sqrt of 15)
A philosophy professor wants to find out whether the mean age of the men in his large lecture class to sequel the mean age of women his in classes. After collecting data from A random sample of his students the professor tested the hypothesis H0:Mm -Mw=0 against the alternative Ha: Mm -Mw not equal to 0. The p-value is 0.003. Which is true?
It is very unlikely that the professor would see results like these is the mean age of men was equal to the mean age of women.
Absorption rates into the body are important considerations when manufacturing a generic version of a brand-name drug. A pharmacist read that the absorption rate into the body of a new generic drug
(G) is the same as its brand-name counterpart (B). She has a researcher friend of hers run a small
experiment to test Ho : Mc - Mg = 0 against the alternative H, : Ha- M # 0. Which of the following
would be a Type I error?
A) Deciding that the absorption rates are different, when in fact they are not.
A two sample t-test for means is conducted with samples whose statistics are given in the table. What is value of the test statistic?
1.20
At one vehicle inspection station, 13 of 52 trucks and 11 of 88 cars failed the emissions test. Assuming these vehicles were representative of the cars and trucks in the area, what is the standard error of the difference in the percentages of all cars and trucks that are not in compliance with air quality regulations?
0.070
At one sat test site students taking the test for a second time volunteered to inhale supplemental oxygen for 10 minutes before the test.in fact, some received oxygen, but others, randomly assigned, were given normal air. Test results showed that 42 of 66 students who breathed oxygen improved their sat score, compared to only 35 of 63 students who did not get the oxygen. Which procedure should we use to see if there is evidence that breathing extra oxygen can help test-takers think more clearly?
2-proportion z-test
A survey asked people “on what percent of days do you get more than 30 minutes of vigorous exercise?” using their responses we want to estimate the difference in exercise between men and women. We should use a
2 proportionZ- interval
Two agronomists analyzed the same data, testing the same null hypothesis about the proportion of tomato plants suffering from blight. One rejected the hypothesis but the other did not. Assuming neither made a mistake in calculations, which of these possible explanations could account for this apparent discrepancy?
I. One agronomist wrote a one-tailed alternative hypothesis, but the other used 2 tails.
II. They wrote identical hypotheses, but the one who rejected the null used a higher a - level.
III. They wrote identical hypotheses, but the one who rejected the null used a lower a - level.
I or II
one or two
