A random sample had 49 values. The sample mean is 8.5 and the sample standard deviation is 1.5. Use a level of significance of 0.01 to conduct a left-tailed test of the claim that the population mean is 9.2. a-is it appropriate to use a student's distribution? Explain. HOw many degrees of freedom do we use? b- what are the hypotheses? c- compute the t value of the sample test statistic.

You work for a soft-drink company in the quality control division. You are interested in the standard deviation of one of your production lines as a measure of consistency. The product is intended to have a mean of 12 ounces, and your team would like the standard deviation to be as low as possible. You gather a random sample of 17 containers. Estimate the population standard deviation at a 98% level of confidence. 11.94 11.93 12.04 11.99 12.06 11.92 11.98 12.11 11.83| 11.88 12.05 11.93 11.96 12.2 11.92 11.82 11.97 (Data checksum: 203.53) Note: Keep as many decimals as possible while making these calculations. If possible, keep all answers exact by storing answers as variables on your calculator or computer. a) Find the sample standard deviation: b) Find the lower and upper x critical values at 98% confidence: Lower: Upper: c) Report your confidence interval for o: (

Moviegoers The average "moviegoer" sees 8.5 movies a year. A moviegoer is defined as a person who sees at least one movie in a theater in a 12-month period. A random sample of 42 moviegoers from a large university revealed that the average number of movies seen per person was 10.2. The population standard deviation is 3.2 movies. At the 0.01 level of significance, can it be concluded that this represents a difference from the national average? Part 1 of 5 State the hypotheses and identify the claim with the correct hypothesis. Hotu = 85 Part: 1/5 not claim H₁ 8.5 claim This hypothesis test is a two-tailed ▼test. Part 2 of 5 ▼ ▼ Find the critical value(s). Round the answer to at least two decimal places. If there is more than one critical value, separate them with commas. Critical value(s): X 0.0.... + 8分民图〗b. E

You work for a soft-drink company in the quality control division.  You are interested in the standard deviation of one of your production lines as a measure of consistency. The product is intended to have a mean of 12 ounces, and your team would like the standard deviation to be as low as possible.  You gather a random sample of 14 containers.  Estimate the population standard deviation at a 95% level of confidence.   12.01 12.02 11.69 12.06 12.08 11.99 12.1 12.04 12 11.93 12.07 11.85 12.01 11.98     (Data checksum: 167.83) Note: Keep as many decimals as  possible while making these calculations. If possible, keep all answers exact by storing answers as variables on your calculator or computer. a)  Find the sample standard deviation:   b)  Find the lower and upper χ2χ2  critical values at 95% confidence:Lower:     Upper:  c)  Report your confidence interval for σσ:  (  ,  )

Good credit: The Fair Isaac Corporation (FICO) credit score is used by banks and other lenders to determine whether someone is a good credit risk. Scores range from 300 to 850 , with a score of 720 or more indicating that a person is a very good credit risk. An economist wants to determine whether the mean FICO score is more than the cutoff of 720 . She finds that a random sample of 120 people had a mean FICO score of 740 with a standard deviation of 90 . Can the economist conclude that the mean FICO score is greater than 720 ? Use the =α0.01 level of significance and the P -value method with the

You work for a soft-drink company in the quality control division.  You are interested in the standard deviation of one of your production lines as a measure of consistency. The product is intended to have a mean of 12 ounces, and your team would like the standard deviation to be as low as possible.  You gather a random sample of 16 containers.  Estimate the population standard deviation at a 90% level of confidence.   11.98 12.11 11.88 11.99 11.89 12.02 11.84 12.05 12.13 11.94 12.31 12 12.07 12.02 12.04 12.04       (Data checksum: 192.31)  Keep as many decimals as  possible while making these calculations. a)  Find the sample standard deviation:   b)  Find the lower and upper χ2χ2  critical values at 90% confidence:Lower:     Upper:  c)  Report your confidence interval for σσ:  (?  , ? )

Milan

You work for a soft-drink company in the quality control division.  You are interested in the standard deviation of one of your production lines as a measure of consistency. The product is intended to have a mean of 12 ounces, and your team would like the standard deviation to be as low as possible.  You gather a random sample of 18 containers.  Estimate the population standard deviation at a 98% level of confidence.   11.98 11.99 11.96 12.09 11.79 11.96 11.87 12.1 12.16 12.03 12.04 12.11 12.12 12.15 11.95 12.23 11.95 12.12   (Data checksum: 216.6) Note: Keep as many decimals as  possible while making these calculations. If possible, keep all answers exact by storing answers as variables on your calculator or computer. a)  Find the sample standard deviation:   b)  Find the lower and upper χ2χ2  critical values at 98% confidence:Lower:     Upper:  c)  Report your confidence interval for σσ:  (  , )

Good credit: The Fair Isaac Corporation (FICO) credit score is used by banks and other lenders to determine whether someone is a good credit risk. Scores range from 300 to 850, with a score of 720 or more indicating that a person is a very good credit risk. An economist wants to determine whether the mean FICO score is more than the cutoff of 720. She finds that a random sample of 40 people had a mean FICO score of 760 with a standard deviation of 95. Can the economist conclude that the mean FICO score is greater than 720? Use the α= 0.01 level of significance and the P-value method and Excel. a)Compute the value of the test statistic. Round the answer to at least three decimal places.  t= ? b) what is the P-value? c) Does it Rejects/Accepts the null hypothesis H_0? d) There is/ is not  enough evidence to conclude that the mean FICO score is lower than the cutoff of 720.