20. A very large population has a mean of 55 and a standard deviation of 8. One day a sample of 40 observations is taken. On another day a sample of 100 observations is taken. Which of the following is true? The standard error of the mean will be smaller with 40 observations. The standard error of the mean will be larger with 40 observations. The standard error of the mean will be the same with either 40 or 100 observations. It is impossible to determine any of the above given the available information.

9. The number of births per woman in China is 1.6 down from 5.91 in 1966. This fertility rate has been attributed to the law passed in 1979 restricting births to one per woman. Suppose that a group of students studied whether or not the standard deviation of births per woman was greater than 0.75. They asked 50 women across China the number of births they had had. The results are shown in the following table. Does the students’ survey indicate that the standard deviation is greater than 0.75? Use α = 0.01. # of Births Frequency         0                5         1               30         2               10         3                5

One of the z-score formulas will help on this question. Scores on the SAT test are normally distributed with a mean of 500 and standard deviation of 100 points. Pretend someone scored 400 on the math portion of the SAT test. What would be the z-score cut off for this score?     A. 1.0   B. -1.0   C. 0   D. 2.0

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