It was observed that 4 out of 10 randomly selected students went to the cinema. Find the 95% confidence interval estimate for the proportion of moviegoers in the population, \pi. P( 0,20 <1< 0,30 ) = 0,95 OA) P( 0,30

An SRS of 100 postal employees found that the average time these employees had worked for the postal service was x = 7 years with standard deviation s = 2 years. Assume the distribution of the time the population of employees have worked for the postal service is approximately Normal. A 95% confidence interval for the mean time u the population of postal service employees have spent with the postal service is 7 + 0.525 7 + 0.4 7 + 2 7 + 1.984 b

A sample of size 65 gave a mean 7.4 and standard deviation as 1.6 then 95% confidence interval for population mean will be Select one: O (17.008, 17.792) O [27.008, 30.008] O (7.008, 7.792) O (9,265, 10.735)

In a data management exam, the scores of 567 participants followed a continuous normal distribution. It is known that the mean from all of the students is 75, and to reach the top 1%, students need to score more than (exactly) 92.    a) Estimate the number of students who scored between 60 and 70.   b) 10 students are good friends. After knowing each other’s marks, they came up with a 95% confidence interval of 65 ± 12 for the population mean. Can you conclude that, with a 90% confidence level, that these students performed worse than average?