1.For a sample size of 100 determine the crtitical value for a two-tail hypothesis test at a 5% level of significance when the population standard deviation is unknown.
2.The SAT scores have an average of 1200 with a standard deviation of 60. A sample of 36 scores is selected. What is the probability that the sample mean will be between 1190 and 1210? Round your answer to three decimal places.
3.The sales of a grocery store had an average of $8,000 per day. The store introduced several advertising campaigns in order to increase sales. To determine whether or not the advertising campaigns have been effective in increasing sales, a sample of 64 days of sales was selected. It was found that the average was $8,225 per day. From past information, it is known that the standard deviation of the population is $1,200. The value of the test statistic is 1.5. The p-value associated with this test statistic is
4.The sales of a grocery store had an average of $8,000 per day. The store introduced several advertising campaigns in order to increase sales. To determine whether or not the advertising campaigns have been effective in increasing sales, a sample of 64 days of sales was selected. It was found that the average was $8,150 per day. From past information, it is known that the standard deviation of the population is $1,200.
The value of the test statistic is
5.Using the Excel function (t.inv) determine the t value for a 95% confidence interval estimation for a sample size of 50. Round your answer to three decimal places.
6.Playbill Magazine reported that the mean annual household income of its readers is $119,155. Assume this estimate of the mean is based on a sample of 80 households, and based on past studies, the population standard deviation is known to be $30,000. What is the margin of error at a 95% level of confidence? Round your answer to two decimal places.
7.
The SAT scores have an average of 1200 with a standard deviation of 60. A sample of 36 scores is selected.
What is the probability that the sample mean will be larger than 1220? Round your answer to three decimal places.