Executives at a car dealership want to estimate the average age of their custome before making a television commercial. They want to be 90% confident that the mean age is ±2 years of the sample mean. If the standard deviation from a previo study is 12 years, how large should the sample be? 98 239 4 139

Are Older men Shorter than younger men? According to a national mean report the theight arus men IS 69.4 Inches. In a sample Between ages 60 and 300 men 69 The mean theight was I 68.7 Inches. Public Health Officials Want to determine whether the mean theight 14 108 For alder men is less than the mean Height All adult men of population standard deviation is Use a=0.65 level of 3.42 Signifigance, and the pratue

A quantitative data set has a size 50. At least how many observations lie within 3standard deviations to either side of the​ mean?

Find the variance and the standard deviation for the following numbers: 1, 5, 6, 8. Show all your work. Do not simplify fractions/products/similar.

A particular fruit's weights are normally distributed, with a mean of 323 grams and a standard deviation of 7 grams.The heaviest 18% of fruits weigh more than how many grams?Give your answer to the nearest gram.

In order to set rates, an insurance company is trying to estimate the number of sick days that full time workers at an auto repair shop take per year. A previous study indicated that the standard deviation was  3.3  days. How large a sample must be selected if the company wants to be  99%  confident that the true mean differs from the sample mean by no more than  1  day?     73     157     90     52

Consider the data from the Anthropology 105 class.  The mean for women is 64.33 in and the standard deviation is 2.64 in. The average height of men in the US is approximately 5ft 10in. What proportion of women represented here are shorter than the average man?

Show complete solution for each item. don't type it. write it on paper

A developmental psychologist is interested in studying how long babies gaze at a photograph of a human face. To test this question, she shows a picture to a sample of six babies and records the length of their gaze in seconds. The data are as follows: 12, 17, 18, 20, 20, 29. Calculate the mean, median, mode, range, variance and standard deviation for the sample.

The president of a college wants to determine the mean number of units that college students take per semester. How large of a sample is required in order to be 99% sure that a sample mean will be off by no more than 1.25 units? An initial study suggested that the standard deviation is approximately 2.1 units.