A random sample of size 10 produced a sample mean equal to 12 and a standard deviation equal to .15 . Based on this information, the upper limit for a 95 confidence interval estimate is approximately 12.107.
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Q. 2All binomial distributions can be approximated very closely by normal distributions.
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Q. 3With all other factors held constant, confidence intervals constructed with small samples tend to have greater margin of error than those constructed from larger samples.
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Q. 4Adding or subtracting 0.5 from the binomial random variable x's interval endpoints (i.e., the so-called continuity correction) improves the normal approximation to the binomial by correcting for or accounting for the missing corners of the probability rectangles corresponding to values of x.
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Q. 5Student's t-distribution is a sampling distribution for a random variable, t, derived from a normally distributed population, that is (1) single-peaked above the random variable's mean, median, and mode of zero, (2) perfectly symmetrical about this central value, and (3) characterized by tails extending indefinitely in both directions from the center, approaching, but never touching, the horizontal axis.
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Q. 6For some positive value of x, the probability that a standard normal variable is between 0 and + 1.5x is 0.4332 . The value of x is:
a. 0.10
b. 0.50
c. 1.00
d. 1.50
e. 2.00
Q. 7The shape of the t-distribution changes as the value of the sample mean changes.
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