STA 2381 Exam 2024|Questions with
Correct Verified Answers
If an estimator has the property that, the larger the sample size, the more likely it is that the
estimate will be close to the population characteristic being estimated, that estimator is said to
be - ANSWER consistent
estimate vs estimator - ANSWER An estimate is a numerical value obtained from a sample
while an estimator is a sample statistic which, prior to sampling, is a random variable
The parameters of a normal probability distribution specify: 1 the variable of the distribution;
2 the skewness of the distribution; 3 the location of the center of the distribution - ANSWER 1
and 3 only
Simple random sampling refers to - ANSWER the method of sample selection
Given the following set of data 4,9,7,7,3,6, the sample mean and sample median
are, respectively - ANSWER 6, 6.5
The sampling distribution of the sample mean: - ANSWER is approximately normally distributed
for sufficiently large sample sizes
The process of making decisions about the values of population parameters based on a sample
data is known as: - ANSWER statistical inference
, Indicate the statement, if any, which does not correctly apply to normal random variables: -
ANSWER They all have the same mean and the same standard deviation
The standard normal random variable differs from other normal random variables in that -
ANSWER The standard normal random variable has mean zero and standard deviation 1.
The sampling distribution of X bar refers to: - ANSWER The distribution of the different possible
values of the sample mean together with their respective probabilities of occurence
The characteristics (parameters) of the sampling distribution of X bar are materially affected
by - ANSWER The sample size, the variability in the population, the mean of the population
A simple random sample of a population is chosen in such a way that: - ANSWER each possible
sample combination has an equal probability of being chosen
The dispersion among sample means is less than the dispersion among the sampled values
themselves because - ANSWER Very large values are averaged down, and very small values
are averaged up
The Central Limit Theorem assures us that the sampling distribution of the sample mean -
ANSWER is always approximately normal for sufficiently large sample sizes
The standard error of the sample mean for a sample size of two or more is - ANSWER
always less than the standard deviation of the population
The central limit theorem - ANSWER Permits us to know the sampling distribution of the sample
mean and, therefore, to know how accurate the sample mean is as an estimator of the
population mean
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