A student's times per week utilization of computer lab are normally distributed, w/ a μ = 6.2 hrs and a σ = 0.9 hour. A student is randomly selected. Determine the likelihood/probability that the student utilizes a computer lab. • more than 8 hrs per week • between 5 & 7 hrs per week

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 = 11 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 = 0.6 hour. Another random sample of n2 = 11 adults showed that they had an average REM sleep time of x2 = 2.20 hours per night. Previous studies show that ?2 = 0.7 hour. Do these data indicate that, on average, children tend to have more REM sleep than adults? Use a 1% level of significance.   State the null and alternate hypotheses. H0: ?1 = ?2; H1: ?1 ≠ ?2 H0: ?1 < ?2; H1: ?1 = ?2     H0: ?1 = ?2; H1: ?1 > ?2 H0: ?1 = ?2; H1: ?1 < ?2 (b) What sampling distribution will you use? What assumptions are you making? The Student's t. We assume…

lengths of human pregnancies are normally distributed with μ = 268 days and  σ = 15 days. I. the probability that a human pregnancy lasts between 240 and 289 days? II. determine the length of the pregnancy such that 85% of the population is smaller that is, what is the 85th percentile for length of pregnancies in humans using the population above. III) what percentage of preganancies end at 37 weeks or prior

Scores on an TOFEL for IT school candidates are normally distributed with μ = 140 and s = 14 What is the probability a candidate will likely score above 160? What percentage of candidates will likely score below 140?