Prob Stat Chapter 5 Practice

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

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

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

A leader of an association of jeepney driver claims that the average daily take-home pay of all jeepney drivers in Caloocan is ₱350.00. A random sample of 100 jeepney drivers in Caloocan was interviewed and the take-home pay was found to be ₱420.00. If 0.05 significance level was used to find out whether the average take home pay is different from ₱350.00 and population variance was assumed to be ₱92.00, what is the appropriate test statistic?

• t-test

• z-test

• left-tailed test

• right-tailed test

L.V. Co. has an average sale of ₱37 million per week from their products in all their outlets. An area manager found out that the average gross sales from the 28 outlets under her jurisdiction is ₱32.5 million per week with standard deviation of ₱1.5 million. Does the mean sales of all outlets differ from the mean sales of the 28 outlets under her jurisdiction? In the given problem, what statistical tool is suitable to use?

• t-test

• z-test

• ANOVA

• Chi-Square

A cellular battery manufacturer claims that his battery when fully charged has mean life of 24 hours with standard deviation of 4 hours. A dealer randomly chose sample of 35 batteries to be tested and resulted to 22.5 hours mean life. In the given situation, 22.5 hours is __________.

• sample mean

• number of sample

• sample standard deviation

• population standard deviation

According to a study, there is an increase on average monthly expenses of ₱250.00 for cell phone loads of Senior High School students in the city. Is there a reason to believe that the amount increased if sample of 60 students has an average monthly expense of ₱280.00 and the population standard deviation is ₱77.00? What is the tool to be used in computing the test value?

• z-test

• t-test

• left-tailed test

• alternative test

In a left-tailed test with 𝛼=0.01, the critical value of z is:

• -2.576

• -2.330

• -1.960

• -1.645

For a two-tailed test with variance unknown, n= 16, and 𝛼=0.05, what is the critical value?

• ±2.092

• ±2.134

• ±2.145

• ±2.125