Question

PLSSS HELP!!! I really need help with this i have tried everything! Please provide instructions so I could learn how to do it! You are interested in finding a 98% confidence interval for the average number of days of class that college students miss each year. The data below show the number of missed days for 11 randomly selected college students. Round answers to 3 decimal places where possible. 9, 1, 2, 2, 9, 10, 1, 3, 7, 4, 2 a. To compute the confidence interval use a ? distribution. b. With 98% confidence the population mean number of days of class that college students miss is between ? and ? days. c. If many groups of 11 randomly selected non-residential college students are surveyed, then a different confidence interval would be produced from each group. About ? percent of these confidence intervals will contain the true population mean number of missed class days and about ? percent will not contain the true population mean number of missed class days.

Answer 1

To compute a 98% confidence interval for the average number of days of class that college students miss, we use the t-distribution. With 98% confidence, the population mean number of days of class that college students miss is between 1.266 and 7.821 days. Approximately 98% of these confidence intervals will contain the true population mean number of missed class days.

Step-by-step explanation:

a. To compute the confidence interval, we use the t-distribution. Since the sample size is small (11 students), we use the t-distribution instead of the normal distribution.

b. With 98% confidence, the population mean number of days of class that college students miss is between 1.266 and 7.821 days. This means that we can be 98% confident that the true population mean falls within this interval.

c. If many groups of 11 randomly selected non-residential college students are surveyed, then approximately 98% of these confidence intervals will contain the true population mean number of missed class days and about 2% will not contain the true population mean number of missed class days.

Answer 2

Step-by-step explanation:

a. When the sample size is below 30 or the population standard deviation is not known, use a t distribution rather than a normal distribution.

b. The confidence interval is:

CI = x ± CV × SE

where x is the sample mean,

CV is the critical value (in this case, t).

and SE is the standard error (the sample standard deviation).

For the data given, the mean is x = 4.545, and the standard deviation is SE = 3.503.

There are 11−1 = 10 degrees of freedom, and the confidence level is 98%. For a t-table, the critical value is CV = 2.764.

So the confidence interval is:

CI = 4.545 ± 2.764 × 3.503

CI = (-5.1, 14.2)

c. The confidence level is 98%, so 98% of these confidence intervals will contain the true population mean, and 2% will not.