n a survey, 23 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $49.5 and standard deviation of $7.5. Estimate how much a typical parent would spend on their child's birthday gift (use(a 80% confidence level). Give your answers to 3 decimal places. Express your answer in the format of ¯x±  E.  $ (?) ± $ (?)

The arm span of a team of athletes was measured and listed in the attached image (Problem-Image2.jpg). a) Calculate the mean arm span, ?̄. b) Complete the table and calculate (to two decimal places of accuracy, the standard deviationof the data.). Check the equation in the attached image (Problem-Image3.jpg)

Assume that the mean height of men in the United States is 70 inches, with a standard deviation of 3 inches.  A particular man is 80 inches tall.  Find the z-score of his height.  (Round to two decimal places.)

You collected data from a random sample of students on their impressions of the university.  On a particular opinion item item, the mean for male students was 15.2 -- with a standard deviation of 3.4. The mean on that item for women was 14.4, with a standard deviation of 3.8. Calculate Cohen's d effect size. IN THE SPACE BELOW, write the effect size AND your interpretation of it.

The mean height of females in a certain country is 66 inches with a standard deviation of 4 inches. Find the height that correspond to a z score of 0.8. Round your answer to one decimal place, if needed.

Help me find which A,B,C, or D is the correct answer to the last part please. The brain volumes ​(cm3​) of 50 brains vary from a low of 904 cm3 to a high of 1490 cm3. Use the range rule of thumb to estimate the standard deviation s and compare the result to the exact standard deviation of 191.4 cm3​, assuming the estimate is accurate if it is within 15 cm3. The estimated standard deviation is 146.5 cm3.     A. The approximation is not accurate because the error of the range rule of​ thumb's approximation is greater than 15 cm3.   B. The approximation is not accurate because the error of the range rule of​ thumb's approximation is less than 15 cm3.   C. The approximation is accurate because the error of the range rule of​ thumb's approximation is greater than 15 cm3.   D. The approximation is accurate because the error of the range rule of​ thumb's approximation is less than 15 cm3.