The random variable for a chi-square distribution may assume
any value between −1 to 1
any value between-infinity to + infinity
any negative value
any value greater than zero
It is known that the variance of a population equals 1,936. A random sample of 121 has
been taken from the population. There is a .95 probability that the sample mean will
provide a margin of error of
7.84
31.36
344.96
1,936
The value added and subtracted from a point estimate in order to develop an interval
estimate of the population parameter is known as the
confidence level
margin of error
parameter estimate
interval estimate
In a sample of 400 voters, 360 indicated they favor the incumbent mayor. The 95%
confidence interval of voters not favoring the incumbent is
0.871 to 0.929
0.120 to 0.280
0.765 to 0.835
0.071 to 0.129
Whenever the estimation process summarizes all of the information a sample has about
a population parameter, the point estimator has the property of
relative consistency
full consistency
sufficiency
unbiasedness
The sampling distribution of the sample means
is the probability distribution showing all possible values of the sample mean
is used as a point estimator of the population mean μ
is an unbiased estimator
shows the distribution of all possible values of μ
A sample of 51 observations will be taken from an infinite population. The population
proportion equals 0.85. The probability that the sample proportion will be between
0.9115 and 0.946 is
0.8633
0.6900
0.0819
0.0345
A population has a mean of 84 and a standard deviation of 12. A sample of 36
observations will be taken. The probability that the sample mean will be between 80.54
and 88.9 is
0.0347
0.9511
0.7200
8.3600
A population has a standard deviation of 16. If a sample of size 64 is selected from this
population, what is the probability that the sample mean will be within ±2 of the
population mean?
0.6826
0.3413
-0.6826
Since the mean is not given, there is no answer to this question.
Use the normal approximation to the binomial distribution to answer this question.
Fifteen percent of all students at a large university are absent on Mondays. If a random
sample of 12 names is called on a Monday, what is the probability that four students
are absent?
0.0683
0.0213
0.0021
0.1329
In the textile industry, a manufacturer is interested in the number of blemishes or flaws
occurring in each 100 feet of material. The probability distribution that has the greatest
chance of applying to this situation is the
normal distribution
binomial distribution
Poisson distribution
uniform distribution
The random variable x is the number of occurrences of an event over an interval of ten
minutes. It can be assumed that the probability of an occurrence is the same in any two
time periods of an equal length. It is known that the mean number of occurrences in ten
minutes is 5.3. The probability that there are less than 3 occurrences is
.1016
.0948
.0659
.1239
If A and B are independent events with P(A) = 0.35 and P(B) = 0.20 , then,
P(A∪ B) =
0.07
0.62
0.55
0.48
A sample of 20 cans of tomato juice showed a standard deviation of 0.4 ounces. A 95%
confidence interval estimate of the variance for the population is
0.2313 to 0.8533
0.2224 to 0.7924
0.0889 to 0.3169
0.0925 to 0.3413
The sampling distribution of the ratio of independent sample variances extracted from
two normal populations with equal variances is the
chi-square distribution
normal distribution
F distribution
t distribution
In order to estimate the average time spent on the computer terminals per student at a
local university, data were collected for a sample of 81 business students over a one
weed period. Assume the population standard deviation is 1.8 hours. If the sample
mean is 9 hours, then the 95% confidence interval is
7.04 to 110.96 hours
7.36 to 10.64 hours
7.80 to 10.20 hours
8.61 to 9.39 hours
The manager of a grocery store has taken a random sample of 100 customers. The
average length of time it took these 100 customers to check out was 3.0 minutes. It is
known that the standard deviation of the population of checkout times is one minute.
With a .95 probability, the sample mean will provide a margin of error of
1.96
0.196
0.10
1.64
Consider the continuous random variable X, which has a uniform distribution over the
interval from 20 to 28. The variance of X is approximately
5.333
2.309
32
0.667
A lottery is conducted using three urns. Each urn contains chips numbered from 0 to 9.
One chip is selected at random from each urn. The total number of sample points in the
sample space is
30
100
729
1000
State the null and alternative hypotheses to be tested.
Compute the test statistic.
What do you conclude about the fairness of this lottery at the 5% level of
significance?
What has been the sample size for this problem?
Perform a t test and determine whether or not supply and unit price are related. Let
α = 0.05 .
Perform and F test and determine whether or not supply and unit price are related.
Let α = 0.05 .
Compute the coefficient of determination and fully interpret its meaning. Be very
specific.
Compute the coefficient of correlation and explain the relationship between supply
and unit price.
We want to determine whether or not the proportions of voters favoring the
Democratic candidate were the same in both states. Provide the hypotheses.
Compute the test statistic.
Determine the p-value; and at 95% confidence, test the above hypotheses.
Determine the standard error of the proportion.
Compute the value of the test statistic.
At 95% confidence, test the above hypotheses.
State the null and alternative hypotheses to be tested.
Compute the test statistic.
At 95% confidence, test the above hypotheses.
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