BUS105 FIRST TRY

Q: If the alternative hypothesis in a hypothesis test includes phrases like “changed”, “not the same” or “different”, the test should be

A: Two-tailed.

Q There is a five-step procedure that systematizes hypothesis testing. Which is not a step in this procedure?

I. Construct a confidence interval.

II. Select the level of significance.

III. Select the test statistic.

A I only

Q A ________ is a single value (statistic) used to estimate a population value (parameter) whereas a ________ is a range of values within which the population parameter is expected to be found.

A POINT ESTIMATE; CONFIDENCE INTERVAL

Q Suppose the alternative hypothesis in a hypothesis test is "the population mean is not equal to 75". If the sample size is 100 and alpha is .05, the critical value (/s) of z is (/are):

A +1.96 & -1.96

Q In a two-tailed hypothesis test with a (alpha) = .10, an investigator wants to determine whether a treatment produces a significant change. What z-score value(s) would define the critical region for this test? Assume population is normal and standard deviation is known.

A z < -1.65 and z > 1.65

Q The distribution of the width of tyres produced is approximated to be normal. An operator randomly selected 25 tyres from the production line and found the sample mean and standard deviation to be 196 mm and 0.05 mm respectively. State the 95% confidence interval for the population mean.

A (195.98, 196.02)

Q Execute an appropriate hypothesis test with p-value=0.02. Which of the following could be a correct conclusion?

A Do not reject the null hypothesis if the level of significance is set at 5% but do reject if the level of significance is set at 1%.

Q A statistics professor has a hunch that the average score of his students has increased and is now above 65 marks (from a maximum of 100 marks). To conduct a hypothesis test for this, the null hypothesis would be

A The population mean is =< 65

Q ______ is the probability of rejecting the null hypothesis when the null hypothesis is true.

A Significance level

Q In order to conduct a 2 sample pooled t-test,

I.     we assume that the samples are from independent populations which are approximately 

      normal.

II.   the sample sizes must be the same.

III.  we assume that the standard deviations of the sampled populations are almost equal.

A I ONLY

Q When the sample size decreases, the

I. population mean decreases.

II. population standard deviation decreases.

III. sampling distribution standard deviation (standard error) increases.

A III only

Q Apply an ANOVA procedure for a two-tailed hypothesis test of the population mean with a large sample size. The observed z value is 1.68, with alpha at 0.05. What would be the correct decision?

A not enough information to make a decision

Q _______ is the level of significance or the probability of a Type I error.

A Alpha (α)

Q As the degrees of freedom decreases, the shape of the t distribution will

A become flatter.

Q If the alternative hypothesis in a hypothesis test includes phrases like “improved”, “declined”, “has reduced” or “has increased”, the test should be

A I only

Q Which of the following is a factor in choosing an appropriate sample size?

I. The desired level of confidence, expressed in terms of z.

II. The maximum allowable error, E, that the researcher will tolerate.

III. The variability in the population under study, measured by σ.

A I, II and III

Q When stating a confidence interval and then increasing the sample size, what will happen to the 95% confidence interval (CI)?

I. The population mean is expected be found within a narrower CI.

II. The population mean is expected be found within a wider CI.

III. The CI becomes a 99% CI.

A I ONLY

Q ______ is the value that is the crossover point between the region where the null hypothesis is not rejected and the region where it is rejected.

A Critical value

Q When the sample size increases, the

I. population mean increases.

II. sampling distribution mean increases.

III. population standard deviation decreases.

A None of the listed choices

Q When executing an appropriate two sample means hypothesis testing, ________________ are characterized by a measurement, then some type of intervention, followed by another measurement. Paired samples are considered to be the same because the same individual or item is a member of both samples.

A Dependent samples

RESULTS: 80/100