The acidity of human​ blood, measured on a pH​ scale, is a normal random variable with a mean of 7.4 and standard deviation of 0.12. Find the probability that the acidity of a​ person's blood has a pH greater than 7.5.   A. 0.1587 B. 0.7967 C. 0.8300 D. 0.1700

Assume that adults have IQ scores that are normally distributed with a mean of μ=105 and a standard deviation σ=20. Find the probability that a randomly selected adult has an IQ between 93 and 117.

Assume the random variable X is normally distributed with mean μ=50 and standard deviation σ=7. Find the 87th percentile.

a random sample of n = 36 students who registered for Introductory Psychology is placed in the online version of the course. At the end of the semester, all students take the same final exam. The average score for the sample is M = 76. For the general population of students taking the traditional lecture class, the final exam scores form a normal distribution with a mean of u = 71. a. If the final exam scores for the population have a standard deviation of o = 12, does the sample provide enough evidence to conclude that the new online course is significantly different from the tra- ditional class? Use a two-tailed test with a = .05. %3D b. If the population standard deviation is o = 18, is the sample sufficient to demonstrate a significant differ- ence? Again, use a two-tailed test with a = ,05. c. Comparing your answers for parts a and b, explain how the magnitude of the standard deviation influ- ences the outcome of a hypothesis test.