Reference no: EM132340593

1. A random sample of 900 SAT scores has a sample mean of 1100. Assume that SAT scores have a population standard deviation of 300.

(a) Construct a 95% confidence interval estimate of the mean SAT scores. Show all work. Just the answer, without supporting work, will receive no credit. Include description of how confidence interval was constructed.

(b) Describe the confidence interval in everyday language.

2. A survey showed that 850 of the 1600 adult respondents who live in a household without landline phones.

(a) Construct a 95% confidence interval estimate of the proportion of adults living in a household without landline phones. Show all work. Just the answer, without supporting work, will receive no credit. Include description of how confidence interval was constructed.

(b) Describe the confidence interval in everyday language.

3. Based on the performance of all individuals who tested between July 1, 2014 and June 30, 2017, the GRE Quantitative Reasoning scores are normally distributed with a mean of 152.8 and a standard deviation of 9.13. (https://www.ets.org/s/gre/pdf/gre_guide_table1a.pdf). Show all work. Just the answer, without supporting work, will receive no credit.

(a) Consider all random samples of 36 test scores. What is the standard deviation of the sample means? (Round your answer to three decimal places)

(b) What is the probability that 36 randomly selected test scores will have a mean test score that is between 150 and 155? (Round your answer to four decimal places)

(c) To get the answer for part (b), what technology did you use? If an online applet was used, list the URL and describe the steps. If a calculator or Excel was used, write out the function