Inverse SATs Critical reading SAT scores are distributed as N 500 , 100 . a. Find the SAT score at the 75th percentile. b. Find the SAT score at the 25th percentile. c. Find the interquartile range for SAT scores. d. Is the interquartile range larger or smaller than the standard deviation? Explain.
Inverse SATs Critical reading SAT scores are distributed as N 500 , 100 . a. Find the SAT score at the 75th percentile. b. Find the SAT score at the 25th percentile. c. Find the interquartile range for SAT scores. d. Is the interquartile range larger or smaller than the standard deviation? Explain.
Solution Summary: The author explains how to determine the SAT score at the 75th percentile.
Inverse SATs Critical reading SAT scores are distributed as
N
500
,
100
.
a. Find the SAT score at the 75th percentile.
b. Find the SAT score at the 25th percentile.
c. Find the interquartile range for SAT scores.
d. Is the interquartile range larger or smaller than the standard deviation? Explain.
Features Features Normal distribution is characterized by two parameters, mean (µ) and standard deviation (σ). When graphed, the mean represents the center of the bell curve and the graph is perfectly symmetric about the center. The mean, median, and mode are all equal for a normal distribution. The standard deviation measures the data's spread from the center. The higher the standard deviation, the more the data is spread out and the flatter the bell curve looks. Variance is another commonly used measure of the spread of the distribution and is equal to the square of the standard deviation.
A well-known company predominantly makes flat pack furniture for students. Variability with the automated machinery means the wood components are cut with a standard deviation in length of 0.45 mm. After they are cut the components are measured. If their length is more than 1.2 mm from the required length, the components are rejected.
a) Calculate the percentage of components that get rejected.
b) In a manufacturing run of 1000 units, how many are expected to be rejected?
c) The company wishes to install more accurate equipment in order to reduce the rejection rate by one-half, using the same ±1.2mm rejection criterion. Calculate the maximum acceptable standard deviation of the new process.
5. Let X and Y be independent random variables and let the superscripts denote
symmetrization (recall Sect. 3.6). Show that
(X + Y) X+ys.
8. Suppose that the moments of the random variable X are constant, that is, suppose
that EX" =c for all n ≥ 1, for some constant c. Find the distribution of X.
Calculus for Business, Economics, Life Sciences, and Social Sciences (14th Edition)
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