A sample of 20 heads of lettuce was selected. Assume that the population distribution of head weight is normal. The weight of each head of lettuce was then recorded. The mean weight was 2.2 pounds with a standard deviation of 0.1 pounds. The population standard deviation is known to be 0.2 pounds. a. Find the z-scores that corresponds to a 90% confidence interval from the normal table. b. Find the error bound (margin of error) for a 90% confidence interval for the population mean weight of the heads of lettuce. Round to three decimal places.

A study wanted to compare the weight loss between two drugs. They sampled 60 people. 30 who took drug A and 30 who took drug B. With drug A the average weight loss was 15 pounds with a standard deviation of 8 pounds. With drug B the average weight loss was 18 pounds with a standard deviation of 9 pounds.  Find the p-value with drug A population 1. Round to 4 decimal places.

A notable indicator of a baby's health is the weight gained in the first year of the baby's life. Assume that the population of all such weight gains for baby girls is approximately normally distributed. A study claimed that the mean of this population is 5.28 kg. As a practicing pediatrician, you want to test this claim. So, you select a random sample of 13 baby girls, and you record the weight each gained in their first year. Follow the steps below to construct a 95% confidence interval for the population mean of all the weight gains for baby girls in their first year. Then state whether the confidence interval you construct contradicts the study's claim. (If necessary, consult a list of formulas.) (a) Click on "Take Sample" to see the results for your random sample. Number of baby girls Sample mean Sample standard deviation Take Sample 13 5.656 1.939 Enter the values of the sample size, the point estimate of the mean, the sample standard deviation, and the critical value you need…

The relationship between birth weight and IQ were studied. 258 subjects with extremely low birth weights had Wechsler IQ scores at age 8 with a mean of 95.5 and a standard deviation of 16.0. For 220 individuals with normal birth weights, the mean at age 8 is 104.9 and the standard deviation is 13.8. Assume that the standard deviations are different, and determine if IQ score appears to be affected by birth weight. Use a = 0.1. 2a. b. Compute a 95% confidence interval on the difference between the means.