In: Statistics and Probability
all hypothesis testing problems must include specification of the null and alternative hypotheses and must report the p-value of the data Standards for automated filling of bulk coffee bean bags require that the mean fill amount should be 10 kg and the s.d. of fill amounts should be no more than 0.01 kg. A random sample of 30 bags was weighed and their weights are given 10.0072 10.0021 10.0105 10.0098 10.0162 9.9756 10.0196 10.0237 10.0432 10.0147 10.053 9.9728 10.0338 9.9446 9.9959 10.0138 10.0019 10.0277 10.0108 10.0462 10.0363 10.0009 9.9761 9.9991 9.9943 10.0134 10.0326 9.9638 9.9973 9.9978 a) Use this data to determine if the mean fill amount differs from 10 at the 5% level of significance. Are the assumptions for this test reasonable? b) What is the probability this test would show a difference if the mean fill amount is 10.01, assuming that the s.d. is no more than 0.015. c) What sample size would be required to show a difference with probability 0.90 if the mean fill amount is 9.95 assuming that the s.d. is no more than 0.015.? Use 5% level of significance. d) Construct a 95% confidence interval for the s.d. of fill amounts.
The sample mean is :
(a)
(b)
Here we need to calculate the power of the test.
(c)
d)
Following is the output of descriptive statistics:
Descriptive statistics | |
X | |
count | 30 |
mean | 10.007823 |
sample standard deviation | 0.024768 |
sample variance | 0.000613 |
minimum | 9.9446 |
maximum | 10.053 |
range | 0.1084 |