The distribution of the amount of money spent by students for textbooks in a semester is approximately normal in shape with a mean of $235 and a standard deviation of $20. According to the standard deviation rule, how much did almost all (99.7%) of the students spend on textbooks in a semester?

The amount spent on textbooks for the fall term was recorded for a sample of five university students - $400, $350, $600, $525, and $450. Calculate the value of the sample standard deviation for the data.Group of answer choices$99.37$450$98.75$250

A bookstore sells books for $2, $3, and $5. Let random variable X = "amount of money for one book."Look at the relative-frequency table below representing the amount of money spent on one item and the relative frequencies with which customers purchase them.x P(X = x)2 .723 .155 .13If the expected amount of money spent by a customer is $2.54, what is the standard deviation?

The amount spent on textbooks for the fall term was recorded for a sample of five hundred university students. The mean expenditure was calculated to be $500 and the median expenditure was calculated to be $425. Which of the following interpretations of the median is correctGroup of answer choices50% of the students sampled had textbook costs equal to $42550% of the students sampled had textbook costs that were less than $425The most frequently occurring textbook cost in the sample was $425The average of the textbook costs sampled was $425

The library checks out an average of 322 books per day, with a standard deviation of 81 books per day. (The number of book check-outs per day is approximately normally distributed)Find the probability that (to 4 dec pl)a) on one day the number of books checked out is less than 200.b) the  mean number of books checked out per day for 32 days will be between 300 and 333.

The amount spent on textbooks for the fall term was recorded for a sample of five hundred university students. It was determined that the 75th percentile was the value $500. Which of the following interpretations of the 75th percentile is correct?Group of answer choices75% of the students sampled had textbook costs that exceeded $500.The average of the 500 textbook costs was $500.25% of the students sampled had textbook costs that exceeded $500.75% of the students sampled had textbook costs equal to $500.