A key characteristic of the chi-square distribution is it   is always skewed   is used with only nominal scale data   it is a based on left tail tests   depends directly on the degrees of freedom

Help me answer questions in picture with the following information below: REM (rapid eye movement) sleep is sleep during which most dreams occur. Each night a person has both REM and non-REM sleep. However, it is thought that children have more REM sleep than adults†. Assume that REM sleep time is normally distributed for both children and adults. A random sample of n1 = 9 children (9 years old) showed that they had an average REM sleep time of x1 = 2.9 hours per night. From previous studies, it is known that ?1 = 0.7 hour. Another random sample of n2 = 9 adults showed that they had an average REM sleep time of x2 = 2.00 hours per night. Previous studies show that ?2 = 0.9 hour. Do these data indicate that, on average, children tend to have more REM sleep than adults? Use a 1% level of significance.

The incomes of math tutors in a tutoring center of a university are normally distributed with a mean of $1100 and a standard deviation of $150 what percentage of tutors earn less than $900 a month

Which procedure is preferred if the procedure must be complete in 26 minutes.