9 Manual Work Consider the following hypothesis test: Ho: 20 Ha: < 20 A sample of 50 provided a sample mean of 19.4. The population standard deviation is 2. (a) Compute the value of the test statistic. (b) What is the p-value? (c ) Using a = .05, what is your conclusion? (d) What is the rejection rule using the critical value? What is your conclusion? Excel Stats functions Q10 Manual Work Consider the following hypotheses test:Ho: 25 Ha: > 25 A sample of 40 provided a sample mean of 26.4. The population standard deviation is 6. (a) Compute the value of the test statistic. (b) What is the p-value? (c ) At a= .01, what is your conclusion? (d) What is the rejection rule using the critical value? What is your conclusion? Excel Stats Work Q11 Manual Work Consider the following hypothesis test: Ho: = 15 Ha: 15 A sample of 50 provided a sample mean of 14.15. The population standard deviation is 3. (a) Compute the value of the test statistic. (b) What is the p-value? (c ) At a = .05. What is your conclusion? (d) What is the rejection rule using the critical value? What is your conclusion? Excel Stats functions Q15 Manual Work Individuals filing federal income tax returns prior to March 31 received an average refund of $1056. Consider the population of "last minute" filers who mail their tax return during the last five days of the income tax period (typically April 10 to April 15). (a) A researcher suggests that a reason individuals wait until the last five days is that on average these individuals receive lower refunds than do early filers. Develop appropriate hypotheses such that rejection of Ho will support the researcher's contention. (b) For a sample of 400 individuals who filed a tax return between April 10 and 15, the sample mean refund was $910. Based on prior experience, a population standard deviation of = $1600 may be assumed. What is the p-value? (c ) At a = .05, what is your conclustion? (d) Repeat the preceding hypothesis test using the critical value approach. Excel Stats Functions Q16 Manual Work In a study entitled How Undergraduate Students Use Credit Cards, it was reported that undergraduate students have a mean credit card balance of $3173 (Sallie Mae, April 2009). This figure was an all-time high and had increased 44% over the previous five years. Assume that a current study is being conducted to determine if it can be concluded that the mean credit card balance for undergraduate students has continued to increase compared to the April 2009 report. Based on previous studies, use a population standard deviation =$1000. (a) State the null and atlernative hypotheses. (b) What is the p-value for a sample of 180 undergraduate students with a sample mean credit card balance of $3325? (c ) Using a .05 level of significance, what is your conclusion? Excel Stats functions Q23 Manual Work Consider the following hypothesis test: ho: 12 ha: > 12 A sample of 25 provided a sample mean = 14 and a sample standard deviation s = 4.32. (a) Compute the value of the test statistic. (b) Use the t distribution table (Table 2 in Appendix B) to compute a range for the p-value. At a = .05, what is your conclusion? (d) What is the rejection rule using the critical value? What is your conclusion? Excel Stats functions Q24 Manual Work Consider the following hypothesis test: Ho: = 18 Ha: 18 A sample of 48 provided a sample mean = 17 and a sample standard deviation s = 4.5. (a) Compute the value of the test statistic. (b) Use the t distribution table ( Table 2 in Appendix B) to compute a range for the p-value. (c ) At a = .05, what is your conclusion? (d) What is the rejection rule using the critical value? What is your conclusion? Excel Stats functions Q25 Manual Work Consider the following hypothesis test: Ho: 45 Ha: < 45 A sample of 36 is used. Identify the p-value and state your conclusion for each of the following sample results, Usa a = .01. (a) = 44 and s = 5.2 (b) = 43 and s = 4.6 (c ) = 46 and s = 5.0 Excel Stats functions Q29 Manual Work (Web file needed) Price The cost of a one-carat VS2 clarity, H color diamond from Diamond Source USA is $5600 (Diamond Source website, March 2003). A midwestern jeweler makes calls to contacts in the diamond district of New York City to see whether the mean price of diamonds there differs from $5600. (a) Formulate hypotheses that can be used to determine whether the mean price in New York City differs from $5600. (b) A sample of 25 New York City contacts provided the prices shown in the file named Diamonds. What is the p-value? At a = .05, can the null hypothesis be rejected? What is your conclusion? (d) Repeat the preceding hypothesis test using the critical value approach? Excel Stats functions 4620 6210 5150 5250 4840 6320 5450 5620 6140 5850 5640 6575 5940 5850 5825 5820 6850 6010 5960 5980 6330 5990 5995 6360 5300 (webfile data) Q32 Manual Work ( webfile needed) According to the National Automobile Dealers Association, the mean price for used cars is $10,192. A manager of Kansas City used car dealership reviewed a sample of 50 recent used car sales at the dealership in an attempt to determine whether the population mean price for used cars at this particular dealership differed from the national mean. The prices for the sample of 50 cars are shown in the file named UsedCars. (a) Formulate the hypotheses that can be used to determine whether a difference exists in the mean price for used cars at the dealership. (b) What is the p-value? ( c ) At a = .05, what is your conclusion? Sale Price (webfile data) 12400 10400 12100 10000 11000 8895 7675 9975 6350 10470 9895 11250 8795 12500 9340 10150 9200 9395 11000 10640 10000 7500 8000 10440 10200 10300 9740 9280 10930 8000 9000 7680 9400 10730 7350 12240 11970 8240 9910 10080 9440 8970 9500 10050 10130 11400 8500 7500 9090 10500 Excel Stats functions