Business Analysis Test
You are the owner of a local fast food restaurant and you want to test whether your average number of customers per day is less than 500. You take a sample of 25 days and find that the average for these days is 480. You have been told by the corporate office that the population standard deviation of the number of customers is 95. What is the critical value for a hypothesis test at a 10% significance level?
-1.29
In testing the hypotheses H0: μ = 75 vs. H1: μ 75, if the value of the test statistic z equals -2.42, then the p-value is:
.0156
A population has a mean of 80 and a standard deviation of 7. A sample of 49 observations will be taken. The probability that the mean from that sample will be larger than 82 is _____.
.0228
A sample of 51 observations will be taken from a process (an infinite population). The population proportion equals .85. The probability that the sample proportion will be between .9115 and .946 is _____.
.0819
A company claims that 10% of the users of a certain allergy drug experience drowsiness. In clinical studies of this allergy drug, 81 of the 900 subjects experienced drowsiness. What is the point estimate for a 95% confidence interval of the proportion of the population that experiences drowsiness?
.09
The manager of a grocery store has selected a random sample of 100 customers. The average length of time it took these 100 customers to check out was 3.0 minutes. It is known that the standard deviation of the checkout time is 1 minute. Refer to Exhibit 8-2. The standard error of the mean equals _____.
.1
In order to estimate the average time spent on the computer terminals per student at a local university, data were collected from a sample of 81 business students over a one-week period. Assume the population standard deviation is 1.2 hours. Refer to Exhibit 8-1. The standard error of the mean is _____.
.133
Random samples of size 100 are taken from a process (an infinite population) whose population proportion is .2. The mean and standard deviation of the distribution of sample proportions are _____.
.2 and .04
The z value for a 97.8% confidence interval estimation is _____.
2.29
A random sample of 121 bottles of cologne showed an average content of 4 ounces. It is known that the standard deviation of the contents (i.e., of the population) is 0.22 ounces. Refer to Exhibit 7-4. In this problem, the .22 is _____.
A parameter
When the level of confidence increases, the confidence interval _____.
Becomes Wider
You are the owner of a local fast food restaurant and you want to test whether your average number of customers per day is less than 500. You take a sample of 25 days and find that the average for these days is 480. You have been told by the corporate office that the population standard deviation of the number of customers is 95. What is your conclusion from a hypothesis test at a 1% significance level?
Fail to reject H 0.
A professor of statistics refutes the claim that the average student spends 3 hours studying for the midterm exam. She thinks they spend less time than that. Which hypotheses are used to test the claim?
H0: μ = 3 vs. H1: μ < 3
A random sample of 25 employees of a local company has been measured. A 95% confidence interval estimate for the mean systolic blood pressure for all company employees is 123 to 139. Which of the following statements is valid
If the sampling procedure were repeated many times, 95% of the resulting confidence intervals would contain the population mean systolic blood pressure.
All of the following are true about the standard error of the mean EXCEPT _____.
It is larger than the standard deviation of the population
A single numerical value used as an estimate of a population parameter is known as a_____.
Point estimate
A Type I error is committed if we make:
an incorrect decision when the null hypothesis is true.
If we change a 95% confidence interval estimate to a 99% confidence interval estimate, we can expect the _____.
width of the confidence interval to increase
The sample mean is the point estimator of _____.
μ