QUIZ #2-STAT-TEst Statistics for Population Mean (Known and Unknown)

Which of the following population parameters is used as a symbol for the mean or average population?

Which of the following statements best describes a parameter?

Which of the following symbols represents population standard deviation?

What test is used when the sample size is below 30 and the population standard deviation is unknown?

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

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

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

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

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 a 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?

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?

A brand of powdered milk is advertised as having a net weight of 250 grams. A curious consumer obtained the net weight of 10 randomly selected cans. The values obtained are 245,248, 242, 245, 246, 248, 250, 245, 243 and 249 grams. Is there reason to believe that the average net weight of powdered milk cans is less than 250 grams at a 5% significance level? Assume the net weight is usually distributed with unknown population variance. What is the appropriate null hypothesis?

A survey reports the mean age at death in the Philippines is 70.95 years old. An agency examines 100 randomly selected deaths and obtains a mean of 73 years with standard deviation of 8.1 years. At 1% level of significance, test whether the agency’s data support the alternative hypothesis that the population mean is greater than 70.95. What is the critical value if this is a two-tailed test?

The Choco-Pabibo Inc. is one of the manufacturers of chocolate toppings which uses a machine to dispense liquid ingredients into bottles that move along a filling line. The owner claims that the machine can dispense at an average of 50 grams with a standard deviation of 0.7 grams. A sample of 35 bottles was selected and it was found out that the average amount dispensed in the sample is 49.3 grams. Test the claims of the owner of the company at 5% level of significance. Use z-test to find the computed value. Type your answer at least 3 decimals in numbers.