Which of the following is desirable for a good point estimator?

• A) All of these
• B) Unbiasedness
• C) Consistency
• D) Efficiency

A failing student is passed by an examiner. It is an example of:

• A) No information regarding student exams
• B) Type II error
• C) Correct decision
• D) Type I error

The standard error of the mean is the:

• A) Sample deviation of the sampling errors
• B) Sample standard deviation
• C) Standard mean of the sample
• D) Standard deviation of the sampling distribution of sample means

A ________ is a range of numbers inferred from the sample that has a certain probability of including the population parameter over the long run.

• A) Confidence interval
• B) Probability limit
• C) Hypothesis
• D) Lower limit

To determine a sample size in estimating population mean, we use the _____value.

• A) f
• B) x
• C) Z
• D) t

The standard error of the sampling distribution of the sample mean when sampling is done with replacement is equal to:

• A) s / n
• B) б/√n
• C) s / (n - 1)
• D) б

If the sampled population has a normal distribution, when is the sampling distribution of the sample mean also a normal distribution?

• A) Always
• B) Only when the sample size is at least 100
• C) Only when the sample size is smaller than 30
• D) Only when the sample size is at least 30

An industrial designer wants to determine the average amount of time it takes an adult to assemble an “easy to assemble” toy. A sample of 16 times yielded an average time of 19.92 minutes, with a population standard deviation equal to 5.73. Assuming normality of assembly times, what is a 95% confidence interval for the mean assembly time?

• A) (17.1123, 30.7277)
• B) (17.1123, 24.7277)
• C) (17.1123, 22.7277)
• D) (14.1123, 22.7277)

“A point estimate plus/minus a few times the standard error of that estimate”. This statement represents:

• A) Acceptance region
• B) Confidence interval
• C) Critical value
• D) Critical region

....... is used when we are dealing with proportions to find the probabilities:

• A) t- distribution
• B) Normal distribution
• C) Both Z & t distribution
• D) F distribution

In sampling without replacement; fpc is not used when:

• A) n>0.05N
• B) n=0.05N
• C) n<=0.05N
• D) None of the above

Alpha is the probability of ……..

• A) Rejecting H1 when it is wrong
• B) Making Type I error
• C) Accepting Ho when it is true
• D) Making Type II error

An experiment was conducted to estimate the mean yield of a new variety of wheat. A sample of 20 plots gave a mean yield of 2.9, and a 95% confidence interval of (2.48, 3.32) . This means:

• A) We are 95% con?dent that the true mean yield of this variety is between 2.48 and 3.32
• B) We are sure the true mean yield of this new variety is between 2.48 and 3.32.
• C) We are 95% confident that the true mean yield of this variety is 2.9
• D) None of these

providing as an estimate a single value calculated from the sample that is likely to be close in magnitude to the unknown parameter is known as

• A) Interval Estimation
• B) None of the above
• C) Estimation
• D) Point Estimation

Total no. of possible samples of size 2 (without replacement) from the population of size 6, will be:

• A) 10
• B) 20
• C) 18
• D) 15

Alpha is the probability of:

• A) All of these
• B) Committing Type I error
• C) Type I error
• D) Reject H0/H0 is true

ß is the probability of:

• A) Accept H0/H0 is false
• B) Reject H0/H0 is false
• C) Reject H0/H0 is true
• D) Accept H0/H0 is true

The standard error of the sampling distribution of differences of means ( x 1 - x 2) ,is equal to:

• A) √((б1+б2)/n)
• B) √((б1)2/n1)+ (б2)2/n2
• C) None of the above
• D) √(б/n)

Sample mean is a/an ........... estimate of population mean.

• A) None of the above
• B) Either unbiased or biased
• C) Unbiased
• D) Biased

In sampling from a large population with sigma = 35, the standard error of the mean is found to be 4 text. The size of the sample used is:

• A) 25
• B) 15
• C) 56
• D) 77