A sample of 25 one-year-old girls had a mean weight of 24.1 pounds with a standard deviation of 4.3 pounds. Assume that the population of weights is normally distributed. A pediatrician claims that the standard deviation of the weights of one-year-old girls is less than 5 pounds. Do the data provide convincing evidence that the pediatrician’s claim is true? (Based on data from the National Health Statistics Reports.)

Pyramid Lake is on the Paiute Indian Reservation in Nevada. The lake is famous for cutthroat trout. Suppose a friend tells you that the average length of trout caught in Pyramid Lake is μ=20 inches. However, a survey reported that of a simple random sample of 37 fish caught, the mean length was 17.5 inches, with an estimated standard deviation of 4.3 inches. Do these data indicate that the average length of a trout caught in Pyramid Lake is less than μ=20 inches? Use α=0.05.   What is the value of the test statistic? (Round your answer to two decimal places.)Find the P-value. (Round your answer to four decimal places.)Based on your results, will you reject or fail to reject the null hypothesis? Are the data statistically significant at level αα? A) At the α=0.05α=0.05 level, we fail to reject the null hypothesis and conclude the data are not statistically significant. B) At the α=0.05α=0.05 level, we reject the null hypothesis and conclude the data are statistically significant. C)…

The mean gas mileage for a hybrid car is 57 miles per gallon. Suppose that the gasoline mileage is approximately normally distributed with a standard deviation of 3.5 miles per gallon.​ What proportion of hybrids gets over 61 miles per​ gallon?

Suppose that the distance of fly balls hit to the outfield (in baseball) is normally distributed with a mean of 250 feet and a standard deviation of 44 feet. Let X = distance in feet for a fly ball. Find the 80th percentile of the distribution of fly balls. (Round your answer to one decimal place.)