Stat & Prob M4

If the variance is known, what test statistic is appropriate?

• t-test

• z-test

• two-tailed test

• one-tailed test

One-sample t-statistic is used instead of one-sample z-statistic when ___________________.

• μ is known.

• σ is known.

• μ is unknown.

• σ is unknown.

Based on the Central Limit Theorem, when the sample (n) is extremely large and the variance is unknown, what is the statistical test to be used?

• t-test

• z-test

• two-tailed test

• one-tailed test

Which of the following is NOT a consideration in using z-test/statistic?

• Variance is known.

• Sample standard deviation is known.

• The population mean is less than 30.

• Population standard deviation is known.

What appropriate tool is applicable if the population is normal, sample standard deviation is known, and sample is less than 30?

• t-test

• z-test

• normal test

• Central Limit Theorem

Which of the following symbols is NOT needed when t-test is used in computing values?

• 𝑛

• μ

• 𝜎

• 𝑠

If in a sample n=16 selected from a normal population, 𝑥̅=56 and 𝑠=12, what statistical test is applicable to be used?

• f-test

• t-test

• z-test

• Central Limit Theorem

Based on Central Limit Theorem, the z-test for single sample may be used when all the following conditions are TRUE except _________________.

• Sample size is less than 30.

• Data are normally distributed.

• Population standard deviation is known.

• Population standard deviation is unknown.

What is the sample standard deviation if a simple random sample of 220 students is drawn from a population of 2,740 college students? Among the sampled students, the average IQ score is 115 with standard deviation of 10.

• 10

• 115

• 220

• 2,740

The supervisor of a certain company claimed that the mean workday of his workers is 8.3 hours per day. A sample of 20 workers was taken and it was found out that the mean workday is 8 hours with standard deviation of 1 hour. At 0.01 level of significance, is the mean workday less than 8.3 hours?

What test statistic is to be used in the given problem?

• z-test

• t-test

• right-tailed test

• left-tailed test