Would you be able to explain step by step with how to get all the solution? And

Question

Would you be able to explain step by step with how to get all the solution? And draw an empirical rule in order for me to understand. THANK YOU!

Use the sample statistics from Exercise 29 and assume the number of vehicles in the sample is 75. The mean speed of a sample of vehicles along a stretch of highways is 67 miles per hour, with a standard deviation of 4 miles per hour. Estimate the percent of vehicles whose speeds are between 63 miles per hour and 71 miles per hour. (Assume the data set has a bell-shaped distribution) (a) Estimate the number of vehicles whose speeds are between 63 miles per hour and 71 miles per hour. (b) In a sample of 25 additional vehicles, about how many vehicles would you expect to have speeds between 63 miles per hour and 71 miles per hour?

Explanation / Answer

mean = 67 , sd = 4

P(63 <X< 71)

note 63 = 67-4 (1 sd below mean)

similarly 71 is 1 sd above mean

hence

68 % is correct by empirical rule

b) 25 * 0.68 = 17 Please rate

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