There are two problems mentioned below. Identify which test (z- or t-test) is used for both problems and give the reason why particular test is used? No need to do calculations.
1.) As an expert on IQ, you know that in the general population of children, the mean IQ = 100, and the population SD = 15 (for the WISC, at least). You also know that IQ is (approximately) normally distributed in the population. Equipped with this information, you can now address questions such as:
If the n=25 children from Dundas are a random sample from the general population of children,
a.) What is the probability of getting a sample mean of 108 or higher?
b.) What is the probability of getting a sample mean of 92 or lower?
2.) A researcher believes that in recent years women have been getting taller. She knows that 10 years ago the average height of young adult women living in her city was 63 inches. The standard deviation is unknown. She randomly samples eight young adult women currently residing in her city and measures their heights. The following data are obtained: [64, 66, 68, 60, 62, 65, 66, 63]