Statistics

1. Last year, the mean dollar spent for online purchases on the AMAZING WEBSITE for the week (7 days) before LABOR DAY among customers who use their Vista Charge Card was $1250. The population standard deviation is not known. Because of increased use of on-line purchasing, Vista’s Vice President of Electronic Marketing believes that purchasing on the AMAZING WEBSITE has increased. She randomly selects 20 customer accounts. The results of the sample found that customers that used Vista charge card spent a mean dollar amount of $1311 on purchases with s = $155. (use alpha 5%) a) State the null and alternative hypothesis in symbols and in words. b) Calculate the expected results for the hypothesis test sampling distribution, assuming the null hypothesis is true. (i.e., name and graph of sampling distribution, mean and standard error) c) Identify the standard distribution that best approximates the sampling distribution. d) Formulate the decision rule(use can use either critical test scores or p-values) e) Determine the statistical results: test statistic, critical test statistic and p-value. f) Determine the conclusion in terms of the null and alternative hypotheses. Do the sample results indicate that the vice president’s claim is supported at alpha = 5%? 2. A sociologist believes that for people under the age of 30, women sleep longer per night on the weekend than men. 16 people were surveyed. Test at alpha =5%. The following summary statistics were determined from the sample. Men Women Mean hrs 10.45 11.18 St dev hrs 0.95 1.81 n 9 7 a) State the Null and Alternate Hypothesis in symbols and in words. b) Calculate the expected results for the hypothesis test sampling distribution, assuming the Null Hypothesis is true. (i.e., name and graph of the sampling distribution, mean and standard error) c) Identify the standard distribution that best approximates the sampling distribution. d) Formulate the decision rule(you can use either critical test scores or p-values) e) Determine the statistical sample results, i.e., the differences between the sample means, the pooled standard deviations, the standard error, the test statistic and p-value. f) Determine the conclusion in terms of the Null and Alternate Hypotheses. Do the sample results indicate that the sociologist’s claim is supported at alpha= 5%? he sociologist’s claim is supported at alpha= 5%?      

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