Using the simple random sample of weights of women from a da

Using the simple random sample of weights of women from a data set, we obtain these sample statistics n 40 andx 146.49 lb. Research from other sources suggests that the population of weights of women has a standard deviation given by o 32.97 lb. a. Find the best point estimate of the mean weight of all women. b. Find 90% confidence interval estimate of the mean weight of all women. Click here to view a t distribution table. Click here to view page 1 of the standard normal distribution table Click here to view age 2 of the standard normal distribution table a. The best point estimate is Type an integer or a decimal.) b. The 90% confidence interval estimate is Ib KH Ib. (Round to two decimal places as needed.)

Solution

a.

The best point estimate is the sample mean, xbar.

Thus,

best point estimate = xbar = 146.49 [ANSWER]

*******************

Note that              
              
Lower Bound = X - z(alpha/2) * s / sqrt(n)              
Upper Bound = X + z(alpha/2) * s / sqrt(n)              
              
where              
              
X = sample mean =    146.49          
z(alpha/2) = critical z for the confidence interval =    1.644853627          
s = sample standard deviation =    32.97          
n = sample size =    40          
              
Thus,              
              
Lower bound =    137.9153538          
Upper bound =    155.0646462          
              
Thus, the confidence interval is              
              
(137.92   ,   155.06) [ANSWER]