In: Statistics and Probability
Workers at a certain soda drink factory collected data on the volumes (in ounces) of a simple random sample of 22 cans of the soda drink. Those volumes have a mean of 12.19 oz and a standard deviation of 0.11 oz, and they appear to be from a normally distributed population. If the workers want the filling process to work so that almost all cans have volumes between 12.03 oz and 12.59 oz, the range rule of thumb can be used to estimate that the standard deviation should be less than 0.14 oz. Use the sample data to test the claim that the population of volumes has a standard deviation less than 0.14 oz. Use a 0.025 significance level. Complete parts (a) through (d) below.
a. Identify the null and alternative hypotheses. Choose the correct answer below.
b. Compute the test statistic.
c. Find the P-value.
d. State the conclusion.
SOLUTION:
From given data,
Workers at a certain soda drink factory collected data on the volumes (in ounces) of a simple random sample of 22 cans of the soda drink. Those volumes have a mean of 12.19 oz and a standard deviation of 0.11 oz, and they appear to be from a normally distributed population. If the workers want the filling process to work so that almost all cans have volumes between 12.03 oz and 12.59 oz, the range rule of thumb can be used to estimate that the standard deviation should be less than 0.14 oz. Use the sample data to test the claim that the population of volumes has a standard deviation less than 0.14 oz. Use a 0.025 significance level.
Mean = = 12.19 oz
Standard deviation = = 0.11 oz
Sample size = = 22
Significance level = = 0.025
a. Identify the null and alternative hypotheses.
Null hypothesis : : > 0.14 oz
Alternative hypothesis : : < 0.14 oz
b. Compute the test statistic.
The test statistic= = (n-1) * s2 /
= (22-1) * 0.112 / 0.142
= 21* 0.112 / 0.142
= 12.964
c. Find the P-value.
Degree of freedom = df = n-1 = 22-1 = 21
P-value = P ( > )
P-value = 1 - P ( < 12.964)
P-value = 1-0.90988
P-value = 0.09012
d. State the conclusion.
Where,
P-value = 0.09012 > Significance level = = 0.025
Then we fail to reject the ,
Hence , there is not sufficient evidence to conclude .