Answer:
The 95% confidence interval of for this random sample is between 128.16 calories and 139.84 calories. This means that we are 95% that the mean number of calories for all bags of potato chips is in this interval.
Step-by-step explanation:
We have the standard deviation for the sample, which means that the t-distribution is used to solve this question.
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 35 - 1 = 34
95% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 34 degrees of freedom(y-axis) and a confidence level of . So we have T = 2.0322
The margin of error is:
In which s is the standard deviation of the sample and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 134 - 5.84 = 128.16 calories
The upper end of the interval is the sample mean added to M. So it is 134 + 5.84 = 139.84 calories
The 95% confidence interval of for this random sample is between 128.16 calories and 139.84 calories. This means that we are 95% that the mean number of calories for all bags of potato chips is in this interval.
