A college student is interested in investigating the claim that students who graduate with a master's degree earn higher salaries, on average, than those who finish with a bachelor's degree. She surveys, at random, 36 recent graduates who completed their master's degrees, and finds that their mean salary is \( \$ 35,000 \) per year. The standard deviation of annual salaries for the population of recent graduates who have master's degrees is known to be \( \$ 3400 \). She also surveys, at random, 48 recent graduates who completed their bachelor's degrees, and finds that their mean salary is \( \$ 34,100 \) per year. The standard deviation of annual salaries for the population of recent graduates with only bachelor's degrees is known to be \( \$ 1100 \). Test the claim at the 0.10 level of significance. Let recent graduates with a master's degree be Population 1 and let recent graduates with a bachelor's degree be Population 2 . Step 2 of 3 : Compute the value of the test statistic. Round your answer to two decimal places.

A professor is concerned that the two sections of college algebra that he teaches are not performing at the same level. To test his claim, he looks at the mean exam score for a random sample of students from each of his classes. In Class 1 , the mean exam score for 14 students is 81.1 with a standard deviation of 7.6 . In Class 2 . the mean exam score for 13 students is 77.4 with a standard deviation of 3.9 . Test the professor's claim at the 0.10 level of significance. Assume that both populations are approximately normal and that the population variances are equal. Let Class 1 be Population 1 and let Class 2 be Population 2 . Step 1 of 3 : state the null and alternative hypotheses for the test. Fill in the blank below. \[ H_{0}: \mu_{1}=\mu_{2} \] \( H_{a}: \mu_{1} \)

A manufacturer fills soda bottles. Periodically the company tests to see if there is a difference between the mean amounts of soda put in bottles of regular cola and diet cola. A random sample of 19 bottles of regular cola has a mean of 499.2 mL of soda with a standard deviation of 2.6 mL . A random sample of 17 bottles of diet cola has a mean of 501.2 mL of soda with a standard deviation of 3.2 mL . Test the claim that there is a difference between the mean fill levels for the two types of soda using a 0.01 level of significance. Assume that both populations are approximately normal and that the population variances are not equal since different machines are used to fill bottles of regular cola and diet cola. Let bottles of regular cola be Population 1 and let bottles of diet cola be Population 2 . Step 3 of 3 : Draw a conclusion and interpret the decision.

A pharmaceutical company needs to know if its new cholesterol drug. Praxor, is effective at lowering cholesterol levels. It believes that people who take Praxor will average a greater decrease in cholesterol level than people taking a placebo. After the experiment is complete, the researchers find that the 36 participants in the treatment group lowered their cholesterol levels by a mean of 20.6 points with a standard deviation of 2.4 points. The 46 participants in the control group lowered their cholesterol levels by a mean of 19.4 points with a standard deviation of 2.1 points. Assume that the population variances are not equal and test the companys claim at the 0.05 level. Let the treatment group be Population 1 and let the control group be Population 2 . Step 1 of 3 : State the null and alternative hypotheses for the test. Fill in the blank below. \[ H_{0}: \mu_{1}=\mu_{2} \] \( H_{a}: \mu_{1} \)

A pharmaceutical company needs to know if its new cholesterol drug, Praxor. is effective at lowering cholesterol levels. It believes that people who take Praxor will average a greater decrease in cholesterol level than people taking a placebo. After the experiment is complete, the researchers find that the 36 participants in the treatment group lowered their cholesterol levels by a mean of 20.6 points with a standard deviation of 2.4 points. The 46 participants in the control group lowered their cholesterol levels by a mean of 19.4 points with a standard deviation of 2.1 points. Assume that the population variances are not equal and test the companys claim at the 0.05 level. Let the treatment group be Population 1 and let the control group be Population 2 . step 2 of 3 : Compute the value of the test statistic. Round your answer to three decimal places.

A manufacturer fills soda bottles. Periodically the company tests to see if there is a difference between the mean amounts of soda put in bottles of regular cola and diet cola. A random sample of 15 bottles of regular cola has a mean of 500.8 mL of soda with a standard deviation of 2.2 mL . A random sample of 18 bottles of diet cola has a mean of 498.3 mL of soda with a standard deviation of 3.6 mL . Test the claim that there is a difference between the mean fill levels for the two types of soda using a 0.01 level of significance. Assume that both populations are approximately normal and that the population variances are not equal since different machines are used to fill bottles of regular cola and diet cola. Let bottles of regular cola be Population 1 and let bottles of diet cola be Population 2 . Step 1 of \( 3: \) State the null and alternative hypotheses for the test. Fill in the blank below.