Afield test for a new exam was given to randomly selected seniors. the exams were graded, and the sample mean and sample standard deviation were calculated. based on the results, the exam creator claims that on the same exam, nine times out of ten, seniors will have an average score within 5% of 75%. is the confidence interval at 90%, 95%, or 99%? what is the margin of error? calculate the confidence interval and explain what it means in terms of the situation.

90% is the answer for confidence interval

Step-by-step explanation:

Given that a field test for a new exam was given.75±0.05(75)

i.e. margin of error =0.05(75)=

The population under study was the seniors. Sample mean and std dev were calculated

Stated that the exam creator ased on the results, that on the same exam, 9 out of 10 seniors will have an average score within 5% of 75%

This implies that 9 out of 10 means in percent 90%

Hence the confidence interval is 90%

SInce 5% of 75 is given the range is 75±(75)

Margin of error =3.75

Confidence interval =(75±3.75)

=(71.25,78.75)

We can interpret this we are 90% confident that  as sample sizes increase, and samples are drawn at random the average grades of seniors would lie between 71.25 and 78.75

introduction, methodology, results, discussion

step-by-step explanation:

an observational study is one which consists of actual observation to record data and then analyse the data.

there are a number of factors that should be analyzed before starting an observational study.

the main four factors are:

i) introduction:   this should be analysed to check whether the purpose of the study is correctly established and the data recorded are appropriate for the study

methodology:   the method of collecting the data, such as whether randomly selected, and whether sample size matches with the population to be studied, whether questions asked are easy to answer by common men, etc.

results: then results such as summary of data with comments should be studied thoroughly

discussion:   the last is the discussion, this can be either by management people or persons who are all interested , etc.