Assume that the time of 50m running of junior high school boy students follows a normal distribution with mean and varia

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Assume That The Time Of 50m Running Of Junior High School Boy Students Follows A Normal Distribution With Mean And Varia 1 (29.49 KiB) Viewed 21 times

Assume that the time of 50m running of junior high school boy students follows a normal distribution with mean and variance 0.72 (unit: seconds). The time of 100 boy students was examined by random sampling and the average value was 7.9 seconds. Answer the following questions. Find the 95% confidence interval. Round the answer to the third decimal place. Do not fill in the unit. (Ex: If 12.3456..., fill 12.346) Lower bound: Upper bound: Find the 99% confidence interval. Round the answer to the third decimal place. Lower bound: Upper bound: What sample size is required in order to reduce the width of the confidence interval by half? Answer in integer. (Do not write the unit.)