E Test: POST UNIT 5 - TEST - Ch. 8 Question 14 of 14 This test: 14 point(s) possible This question: 1 point(s) possible Submit test A researcher studying public opinion of proposed Social Security changes obtains a simple random sample of 35 adult Americans and asks them whether or not they support the proposed changes. To say that the distribution of the sample proportion of adults who respond yes, is approximately normal, how many more adult Americans does the researcher need to sample in the following cases? (a) 10% of all adult Americans support the changes (b) 15% of all adult Americans support the changes (a) The researcher must ask more American adults. (Round up to the nearest integer.) (b) The researcher must ask more American adults. (Round up to the nearest integer.)This test: 14 point(s) @ possible This question: 1 point(s) Submit test possible E Test: POST UNIT 5 - TEST - Ch. 8 Question 4 of 14 Assume that blood pressure readings are normally distributed with a mean of 123 and a standard deviation of 6.4. If 64 people are randomly selected, nd the probability that their mean blood pressure will be less than 125. Round to four decimal places. O A. 0.0062 0 B. 0.8615 0 c. 09990 O D. 0.9938 : Test: POST UNIT 5 - TEST - Ch. 8 Question 6 of 14 \"\"5 \"5\" '4 WW 955\"? () Submittest This question: 1 point(s) posstble Suppose a geyser has a mean time between eruptions of 7'2 minutes. Let the interval oftime between the eruptions be normally distributed with standard deviation 29 minutes. Complete parts (a) through (9) below. The probability that the mean of a random sample of 33 time intervals is more than 84 minutes is approximately 0.0087 . (Round to four decimal places as needed.) (d) What effect does increasing the sample size have on the probability? Provide an explanation for this result. Fill in the blanks below. If the population mean is less than 84 minutes, then the probability that the sample mean of the time between eruptions is greater than 84 minutes decreases because the variability in the sample mean decreases as the sample size increases. (e) What might you oonclude it a random sample of 33 time intervals between eruptions has a mean longer than 84 minutes? Select all that apply. [I A. The population mean may be greater than 72. E] E. The population mean is 72, and this isjusta rare sampling. [I C. The population mean must be more than 72, since the probability is so low. [I D. The population mean must be less than 72, since the probability is so low. E] E. The population mean cannot be 72, since the probability is so low. [I F. The population mean is 72, and this is an example of a typical sampling result. E] G. The population mean may be less than 72