Mathematics
| Question 8
1. (Percentile) The weight of a product is normally distributed with a mean of four ounces and a variance of .25 “squared ounces.” The company wants to classify the unit as a scrap in a maximum of 1% of the units if the weight is below a desired value. Determine the desired weight such that no more than 1% of the units are below it.
1 points Question 9 1. (Percentile) An aptitude test has a mean score of 80 and a standard deviation of 5. The population of scores is normally distributed. What raw score corresponds to the 70th percentile?
1 points Question 10 1. (Percentile) During the past six months, 73.2% of US households purchased sugar. Assume that these expenditures are approximately normally distributed with a mean of $8.22 and a standard deviation of $1.10. 99% of the households spent less than what amount?
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Question 1
1. For any sampled population, the population of all sample means is approximately normally distributed.
True
False
1 points
Question 2
1. If a population is known to be normally distributed, then it follows that the sample standard deviation must equal σ.
True
False
1 points
Question 3
1. If the sampled population is exactly normal distribution, then the sampling distribution of is also expected to be normal regardless of the sample size.
True
False
1 points
Question 4
1. The mean of the sampling distribution of is always equal to the mean of the sampled population.
True
False
1 points
Question 5
1. The central limit theorem states that as the sample size increases the distribution of the sample ________ approach the normal distribution.
| medians | ||
| means | ||
| standard deviations | ||
| variances |
1 points
Question 6
1. As the sample size ______________ the variation of the sampling distribution of ___________.
| Decreases, decreases | ||
| Increases, remains the same | ||
| Decreases remains the same | ||
| Increases, decreases | ||
| None of the above |
1 points
Question 7
1. If the sampled population has a mean 48 and standard deviation 16, then the mean and the standard deviation for the sampling distribution of for n = 16 are:
| 4 and 1 | ||
| 12 and 4 | ||
| 48 and 4 | ||
| 48 and 1 | ||
| 48 and 16 |
1 points
Question 8
1. A manufacturing company measures the weight of boxes before shipping them to the customers. If the box weights have a population mean and standard deviation of 90 lbs. and 24 lbs. respectively, then based on a sample size of 36 boxes, the probability that the average weight of the boxes will exceed 94 lbs. is:
| 34.13% | ||
| 84.13% | ||
| 15.87% | ||
| 56.36% | ||
| 16.87% |
1 points
Question 9
1. A manufacturing company measures the weight of boxes before shipping them to the customers. If the box weights have a population mean and standard deviation of 90 lbs. and 24 lbs. respectively, then based on a sample size of 36 boxes, the probability that the average weight of the boxes will be less than 84 lbs. is:
| 16.87% | ||
| 93.32% | ||
| 43.32% | ||
| 6.678% | ||
| 84.13% |
1 points
Question 10
1. In a manufacturing process a machine produces bolts that have an average length of 3 inches with a variance of .03. If we randomly select three bolts from this process: What is the standard deviation of the sampling distribution of the sample mean?
| .03 | ||
| .01 | ||
| .1732 | ||
| .0577 | ||
| .10 |