Business Statistics TEST - NEED HELP NOW ON IT NOT LATER
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question_1.docxQuestion 1
1. A random sample of 121 mortgage loan applications was selected and it was found that the mean number of days from application until closing was 65 days. From past information, it is known that the standard deviation of the population is 22 days. The standard error of the mean is _________________.
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22.00 |
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96.60 |
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4.24 |
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2.00 |
4 points
Question 2
1. A random sample of 121 mortgage loan applications was selected and it was found that the mean number of days from application until closing was 65 days. From past information, it is known that the standard deviation of the population is 22 days.
If instead of 121, the sample size was 100 and all other factors remain unchanged, the confidence interval to estimate the population mean (μ) would ________________________.
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not change |
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become narrower |
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become wider |
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become zero |
4 points
Question 3
1. A consumer products company wants to increase the absorption capacity of a sponge. Based on past data, the average sponge could absorb 3.5 ounces. After the redesign, the absorption amounts of a sample of sponges were (in ounces): 4.1, 3.7, 3.3, 3.5, 3.8, 3.9, 3.6, 3.8, 4.0, and 3.9.
At the 0.01 level of significance, what is the decision rule to test if the new design increased the absorption of the sponge?
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Reject null hypothesis if computed t is less than 2.580. |
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Reject null hypothesis if computed t is greater than 2.821. |
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Reject null hypothesis if computed z is 1.96 or larger. |
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Reject null hypothesis if computed t is less than 2.764. |
Question 7
1. An electronics retailer believes that, at most, 40% of their cell phone inventory was sold during November. The retailer surveyed 80 dealers and found that 38% of the inventory was sold. Since 38% is less than 40%, is this difference of 2 percentage points sampling error or a significant difference? Test at the 0.05 level. The computed z = -0.37.
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The 2% is a significant difference. |
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We cannot determine if the 2% is a significant difference. |
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There is not enough information to reach a conclusion. |
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None Apply. |
4 points
Question 8
1. The claim that "40% of those persons who retired from an industrial job before the age of 60 would return to work if a suitable job was available" is to be investigated at the 0.02 significance level. If 74 out of the 200 workers sampled said they would return to work, what is our decision?
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Do not reject the null hypothesis because -0.879 lies in the region between +2.326 and -2.326. |
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Do not reject the null hypothesis because -0.879 lies in the region between +2.5760 and -2.576. |
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Reject the null hypothesis because 37% is less than 40%. |
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Do not reject the null hypothesis because 37% lies in the area between 0% and 40%. |
4 points
Question 9
1. The mean annual income of certified welders is normally distributed with a mean of $50,000 and a population standard deviation of $2,000. The ship building association wishes to find out whether their welders earn more or less than $50,000 annually. The alternate hypothesis is that the mean is not $50,000. If the level of significance is 0.10, what is the decision rule?
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Do not reject the null hypothesis if computed z lies between -1.645 and +1.645; otherwise, reject it. |
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Do not reject the null hypothesis if computed z is greater than 1.645; otherwise, reject it. |
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Do not reject the null hypothesis if computed z lies between -1.960 and +1.960; otherwise, reject it. |
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Reject the null hypothesis if computed z is below -1.960; otherwise, reject it. |
4 points
Question 10
1. It is claimed that in a case of auto parts, less than 10% are defective. A sample of 400 parts is examined and 50 are found to be defective. What is the null hypothesis?
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H0: p ≠ 0.10 |
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H0: p ≥ 0.10 |
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H0: p ≤ 0.10 |
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H0: p < 0.10 |
4 points
Question 11
1. It is claimed that in a case of auto parts, less than 10% are defective. A sample of 400 parts is examined and 50 are found to be defective. What is the alternate hypothesis?
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H1: p ≥ 0.10 |
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H1: p > 0.10 |
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H1: p ≤ 0.10 |
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H1: p < 0.10 |
4 points
Question 12
1. It is claimed that in a case of auto parts, less than 10% are defective. A sample of 400 auto parts is examined and 50 are found to be defective. What is the p-value?
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0.0250 |
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0.4525 |
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0.9525 |
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0.0500 |
Question 15
1. There are 2,000 eligible voters in a precinct. A total of 500 voters are randomly selected and asked whether they plan to vote for the Democratic incumbent or the Republican challenger. Of the 500 surveyed, 350 said they would vote for the Democratic incumbent. Using the 0.99 confidence coefficient, what are the confidence limits for the proportion that plan to vote for the Democratic incumbent?
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0.647 and 0.753 |
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0.612 and 0.712 |
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0.397 and 0.797 |
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0.826 and 0.926 |
4 points
Question 16
1. The mean weight of trucks traveling on a particular section of I-475 is not known. A state highway inspector needs an estimate of the population mean. He selects and weighs a random sample of 49 trucks and finds the mean weight is 15.8 tons. The population standard deviation is 3.8 tons. What is the 95% confidence interval for the population mean?
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14.7 and 16.9 |
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13.2 and 17.6 |
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10.0 and 20.0 |
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16.1 and 18.1 |
Question 21
1. A survey of 25 grocery stores revealed that the mean price of a gallon of milk was $2.98, with a standard error of $0.10. If 90% and 95% confidence intervals were developed to estimate the true cost of a gallon of milk, what similarities would they have?
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Both have the same confidence level |
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Both use the same t statistic |
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Both use the same z statistic |
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Both use the same point estimate of the population mean |
