Question

Refrigerator manufacturers design their freezer units to maintain temperatures within a certain range. Suppose a major refrigerator manufacturer wants the temperature of a particular model to have a standard deviation equal to

4degrees°F.

The company tested the freezer under normal operation conditions. The table to the right shows the freezer temperature readings in degrees Fahrenheit. What is test statistic? ?

3.6 6.2 -2 1.2 5 -5.5 5.6 -5.7 0.5 -6.1 -6.1 0.6 -0.8 -1 -5.9

Answer 1

data

3.6   6.2   -2   1.2   5   -5.5   5.6   -5.7   0.5   -6.1   -6.1   0.6   -0.8   -1   -5.9

sd = s =

4.47381

= (15 - 1)*4.47381^2/4^2

= 17.5131039266

df = n-1 = 14

chi-critical value

1) left = =CHISQ.INV(0.025,14) = 5.628

2) right = =CHISQ.INV(0.975,14) = 26.11895

since TS lies between critical values

we fail to reject the null hypothesis at 5 % lvel of signifiance