20% of drivers don't use turn signals, observed of 140 cars.  What is the standard deviation of those who did not use turn sig

If the standard error,  of a sample data set is 5 and the standard deviation,  of the distribution is 45, how many data points, n are in the sample data set?

The Sum of Squared Errors for a data set of 18 numbers is 64. What is the standard deviation? (Enter an exact number as an integer, fraction, or decimal.)

How is standard deviation a measure of distance?

What is the lowest standard deviation value ?

On the final exam, Jenny’s class had an average of 62.4% with a standard deviation of10.4. If the class has 28 students, how many of them failed the exam? (below 50% is fail)

Assume that the mathematics scores on the SAT are normally distributed with a mean of 500 and a standard deviation of 100. What percent of students who took the test have a mathematics score below 610​?

The results of a common standardized test used in psychology research is designed so that the population mean is 175 and the standard deviation is 20. A subject earns a score of 227. What is the z-score for this raw score? Do not round your answer.z-score =    ?

Assume that adults have IQ scores that are normally distributed with a mean of 100 and a standard deviation 20. Find Upper P 4 which is the IQ score separating the bottom 44​% from the top 96​%.

A standardized test has a pop. mean of 152 and a standard deviation of 16. What would be the median raw score for this exam?