find an 80th percentile of the distribution of the average of 49 flyballs

Head circumferences of some males have a bellshaped distribution with a mean of 57 centimeters and a standard deviation of 3 centimeters. What is the variance of head circumferences of adult males?

Describe  the scores in a sample  that has a standard  deviation of zero

Steel rods are manufactured with a mean length of 28 centimeters. because because of variability in the manufacturing process, the lengths of the rods are approximately normally distrubuted with a standard deviation of 0.06. Any rods that are shorter than 27.85 cm or longer than 28.15 cm are discarded. What proportion of rods will be discarded?   Round to 4 decimal places.

Suppose that water usages in American showers are normally distributed, with an average shower using 16.4 gallons, and a standard deviation of 3.7 gallons. Estimate the percentage of showers that used between 9 and 23.8 gallons more than 27.5 gallons less than 12.7 gallons between 9 and 20.1 gallons

The U.S. Center for Disease Control reports that in year 1900, the mean life expectancy is 47.6 years for whites and 33 years for nonwhites. (Click here for reference data) Suppose a survey of randomly selected death records for white and nonwhite people born in 1900 from a certain county is conducted. Of the 110 whites surveyed, the mean life span was 48.2 years with a standard deviation of 11.2 years and of the 95 nonwhites, the mean life span was 39.3 years with a standard deviation of 16 years. Conduct a hypothesis test at the 0.05 level of significance to determine whether there was no difference in mean life spans in the county for whites and nonwhites in year 1900. Preliminary: Is it safe to assume thatnw≤5% of all white people born in 1900 andnnw≤5% of all nonwhite people born in 1900? No Yes Is nw≥30 and nnw≥30 ? No Yes   Test the claim: Determine the null and alternative hypotheses. H0: μw      μnw Ha: μw      μnw  Determine the test statistic. Round to four…

Suppose that the distance of fly balls hit to the outfield is normally distributed with a mean of 252 feet in a standard deviation of 50 feet find the 70th percentile of the distribution of the average of 49 fly balls

Suppose that the distance of fly balls hit to the outfield (in baseball) is normally distributed with a mean of 260 feet and a standard deviation of 50 feet. We randomly sample 49 fly balls.   -Find the 70th percentile of the distribution of the average of 49 fly balls

Assuming that the heights of college women are normally distributed with a mean of 62 inches and standard deviations 3.5 inches, what percentage of woman are taller than 62 inches?

Suppose that annual precipitation is normally distributed, with mean 50 inches, and standard deviation 12 inches. Find the 65th percentile of the precipitation distribution