The average mpg usage for a 2017 Toyota Prius for a sample of 7 tanks of gas was 43.5 with a standard deviation of 1.8. For a 2017 Ford Fusion, the average mpg usage for a sample of 7 tanks of gas was 39.9 with a standard deviation of 2.0.   Assuming equal variances, at α = .05, is the true mean mpg lower for the Ford Fusion?   (a-2) Calculate the tcalc. (Round your answer to 4 decimal places.)   tcalc  ____________    (b) Calculate the p-value using Excel. (Round your answer to 4 decimal places.)   p-value  ___________

In a sample of 12 randomly selected high school​ seniors, the mean score on a standardized test was 1182 and the standard deviation was 161.6.Further research suggests that the population mean score on this test for high school seniors is 1012. Does the​ t-value for the original sample fall between −t0.95 and t0.95​? Assume that the population of test scores for high school seniors is normally distributed.   What is The​ t-value?   And does or does not it not  fall between −t0.95 and t0.95 because t0.95=? ​(Round to two decimal places as​ needed.)

A recent study of 100 social workers in a southern state found that their mean salary was $23,000 with a standard deviation of $2100. A similar study of 95 social workers in a western state found that their mean salary was $34,200 with a standard deviation of$3200.   Find the test statistic and critical value when the claim that the mean salaries of social workers in the western state is greater than that of social workers in the southern state. Use α = 0.05. Sample1:  Social workers in a southern state,  Sample2:  Social workers in awestern state. a) Find the test statistic  b) Find critical value

Suppose babies born after a gestation period of 32 to 35 weeks have a mean weight of 2600 grams and a standard deviation of 600 grams while babies born after a gestation period of 40 weeks have a mean weight of 2900 grams and a standard deviation of 440 grams. If a 35-week gestation period baby weighs 2775 grams and a 40-week gestation period baby weighs 3075 grams, find the corresponding z-scores. Which baby weighs more relative to the gestation period? Find the corresponding z-scores. Which baby weighs relatively more? Select the correct choice below and fill in the answer boxes to complete your choice. (Round to two decimal places as needed.) A. The baby born in week 40 weighs relatively more since its z-score, is smaller than the z-score of for the baby born in week 35. B. The baby born in week 40 weighs relatively more since its z-score, is larger than the z-score of for the baby born in week 35. O C. The baby born in week 35 weighs relatively more since its z-score, is larger…

The mean measured verbal IQ ( IQV) score of a random sample of 20 children was 86.9 with a  standard deviation of 18.5. the mean measured performance IQ score (IQP) of a random sample of 20 children was 101.8 with a standard deviation of 20.0. Using the Critical Value Method and alpha = 0.005 to test the claim that the mean IQV is less than the mean IQP. Assume the population variance are not equal (so use unpooled)

Have American males (AMs) gotten heavier over the last 20 years? A random sample 77 AMs in 2019 had a mean weight of x = 189.030 pounds. A random sample 93 AMs in 1999 had a mean weight of y = 184.795 pounds. It is recognized that the true standard deviation of 2019 AMs weights is σx = 14.04 pounds while it is recognized that the true standard deviation of 1999 AMs weights is σy = 10.03 pounds. The true (unknown) mean of 2019 AMs weights is μx pounds, while the true (unknown) mean of 1999 AMs weights is μy pounds. Weights are known to be a normally distributed. In summary: Type Sample Size Sample Mean Standard Deviation 2019 Data (X) 77 189.030 14.04 1999 Data (Y) 93 184.795 10.03 d) Calculate the standard deviation of X - Y? . e) If we wish to create an 98% confidence interval for μx-μy then what is the z critical value used? f)Create an 98% confidence interval for μx-μy .

A psychologist is studying smokers' self-images, which she measures by the self-image (SI) score from a personality inventory. For adults in the U.S., the mean SI score from this inventory is about 150.  The psychologist gathers a random sample of 16 SI scores of smokers and finds that their mean is 130 and their standard deviation is 31. Assume that the population of SI scores of smokers is normally distributed with mean μ. Based on the sample, can the psychologist conclude that μ is different from 150? Use the 0.05 level of significance. Perform a two-tailed test. Then fill in the table attached. Carry your intermediate computations to at least three decimal places and round your answers as specified in the table.