Goodness of fit - estimation of parameters - Normal Distribution

The waist measurement of a sample of 100 members of a slimming group was taken at the beginning of their weight loss journey.
Waist Measurement, (inches), x Frequency
x ≤ 27 2
28 ≤ x ≤30 12
31 ≤ x ≤ 33 21
34 ≤ x ≤ 36 28
37 ≤ x ≤ 39 26
40 ≤ x 11

a. Estimate the mean and the standard deviation of the population from which these observations were taken. (For these calculations you should assume that the first and last classes have the same width as the other classes.)
b. Use the χ2 distribution and a 1% level of significance to test the adequacy of the normal distribution as a model for these data.