A customer service representative was interested in comparing the average time (in minutes) customers are placed on hold when calling Southern California Edison and Southern California Gas companies. The representative obtained two independent random samples and calculated the following summary information: So Cal Edison      Southern Cal Edison Southern Cal Gas Sample Size 9 12 Sample Mean 3.2 min 2.8 min Sample Standard deviation 0.5 min 0.7 min     Assume the distributions of time a customer is on hold are approximately normal. Using the following null and alternate hypothesis: H0:mu1-mu2=0 vs. Ha:mu1-mu2 not equal 0 Test statistic is t=-1.455 Assume alpha = 0.1 what is the appropriate conclusion for this test?   A. Reject Ha   B. Reject H0   C. Do not reject H0   D. none of these

A study was done using a treatment group and a placebo group. The results are shown in the table. Assume that the two samples are independent simple random samples selected from normally distributed populations, and do not assume that the population standard deviations are equal. Complete parts (a) and (b) below. Use a 0.10 significance level for both parts. a. Test the claim that the two samples are from populations with the same mean. What are the null and alternative hypotheses? OA. Ho H1 H2 H₁: H1 H2 o C. Ho: H = 2 H₁: H1 H2 OB. Ho: H1 H2 H1 H1 H2 OD. Ho H1 H2 H₁: 12 Treatment Placebo μ H1 H2 n 27 31 X 2.35 2.65 S 0.95 0.55

The numbers of incorrect answers on a twe or false competency test for a random sample of 15 students were record. as follows: 2, 1, 3, 0, 1, 3, 6, 0, 3, 3, 5, 2. 1, 4, and 2. d. range. e. standard deviation. f. variance

Treatment Placebo 3. H1 H2 table. Assume that the two samples are independent simple random samples selected from normally distributed populations, and do not assume that the population standard deviations are equal. Complete parts (a) and (b) below. Use a 0.05 significance level for both parts. A study was done using a treatment group and a placebo group. The results are shown in the 27 40 In 2.39 2.65 0.95 0.57 a. Test the claim that the two samples are from populations with the same mean. What are the null and alternative hypotheses? O A. Ho: H1 = H2 O B. Ho: H1H2 D. Ho: H1 H2 The test statistic, t, is (Round to two decimal places as needed.) The P-value is (Round to three decimal places as needed.) State the conclusion for the test. O A. Fail to reject the null hypothesis. There is sufficient evidence to warrant rejection of the claim that the two samples are from populations with the same mean. O B. Reject the null hypothesis. There is not sufficient evidence to warrant rejection…