In hypothesis testing, the critical value is
the largest value of the test statistic that will result in the rejection of the null hypothesis
What a measure of dispersion is?
is a non-negative real number that is zero if all the data are the same and increases as the data become more diverse.
Z is a standard normal random variable. What is the value of z if the area between -z and z is 0.754?
?
After the data has been arranged from smallest value to largest value, the value in the middle is called the
Median
The control limits for an x-bar chart are how many standard deviations above and below the process mean?
3
A measure of the average value of a random variable is called a(n)
expected value
If the coefficient of determination is a positive value, then the regression equation
could have either a positive or a negative slope
Excel's NORMSINV function can be used to compute
the inverse of the Standard Normal Cumulative Distribution Function for a supplied probability value.
A __________ can be used to graphically present quantitative data
bar graph
For any continuous random variable, the probability that the random variable takes on exactly a specific value is
almost zero
Since the population is always larger than the sample, the value of the sample mean
could be larger, equal to, or smaller than the true value of the population mean.
For the standard normal probability distribution, the area to the left of the mean is
0.5
A sample of five Fortune 500 companies showed the following revenues ($ millions): 7505.0, 2904.7, 7208.4, 6819.0, and 19500.0. Based on this information, which of the following statements is correct?
An estimate of the average revenue for all Fortune 500 companies is 8787.42 ($ millions).
A population consists of 8 items. The number of different simple random samples of size 3 (without replacement) that can be selected from this population is
56
A numerical measure of linear association between two variables is the
covariance/correlation coefficient
Excel provides functions for computing the
?
A regression analysis between sales (in $1000) and price (in dollars) resulted in the following equation = 50,000 - 8x
increase of $1 in price is associated with a decrease of $8000 in sales.
Excel's __________ function can be used to compute the mean.
average
A numerical measure from a sample, such as a sample mean, is known as
a statistic
In hypothesis testing, the alternative hypothesis is
a claim about a population parameter that will be true if the null hypothesis is false.
A measure of the strength of the relationship between two variables is the
Regression
The expected value of the random variable is
the value of a random variable one would "expect" to find if one could repeat the random variable process an infinite number of times and take the average of the values obtained.
The sample statistic s is the point estimator of
o
Six Sigma represents a quality level of at most __________ defects per million opportunities.
3.4
The relative frequency of a class is computed by
dividing the frequency of the class by the sample size
Independent simple random samples are taken to test the difference between the means of two populations whose variances are not known. The sample sizes are n1 = 32 and n2 = 40. The correct distribution to use is the
t distribution with 70 degrees of freedom
The coefficient of determination is equal to the
the square of the correlation coefficient.
A frequency distribution is
an arrangement of the values that one or more variables take in a sample.
For a standard normal distribution, a negative value of z indicates
that X was less than the mean U. Z is the number of standard deviations from the mean.
Compared to the confidence interval estimate for a particular value of y (in a linear regression model), the interval estimate for an average value of y will be
narrower
In a questionnaire, respondents are asked to record their age in years. Age is an example of a
quantitative variable
A statistics teacher wants to see if there is any difference in the abilities of students enrolled in statistics today and those enrolled five years ago. A sample of final examination scores from students enrolled today and from students enrolled five yea
(-9.92 to -2.08)
The numbers of hours worked (per week) by 400 statistics students are shown below. If a cumulative frequency distribution is developed for the above data, the last class will have a cumulative frequency of
400
Information on the type of industry is provided for a sample of 50 Fortune 500 companies.The percent frequency of industries that are classified as electronics is?
?
The following information was obtained from matched samples. If the null hypothesis is tested at the 5% level, the null hypothesis
should not be rejected
The following information was obtained from matched samples.
The daily production rates for a sample of workers before and after a training program are shown below. The null hypothesis to be tested is H0: md = 0. The test statistic is
0
In a sample of 800 students in a university, 160, or 20%, are Business majors. Based on the above information, the school's paper reported that "20% of all the students at the university are Business majors." This report is an example of
descriptive statistics
Ordinary arithmetic operations are meaningful
only with quantitative data
Which of the following is not a characteristic of the normal probability distribution?
The graph of the curve is the shape of a rectangle
The numbers of hours worked (per week) by 400 statistics students are shown below.
Number of hours
Frequency
0 - 9
20
10 - 19
80
20 - 29
200
30 - 39
100
Refer to Exhibit 2-1. If a cumulative frequency distribution is developed for the above data, the last
400
Exhibit 9-3
n = 49 H0: m = 50
nar022-1.jpg = 54.8 Ha: m � 50
s = 28
Refer to Exhibit 9-3. The test statistic equals
1.2
A manufacturer wants to estimate the proportion of defective items that are produced by a certain machine. A random sample of 50 items is taken. Which Excel function would not be appropriate to construct a confidence interval estimate?
STDEV
A numerical measure from a sample, such as a sample mean, is known as
a statistic
The proportion of the variation in the dependent variable y that is explained by the estimated regression equation is measured by the
coefficient of determination
The basis for using a normal probability distribution to approximate the sampling distribution of x and p is
the central limit theorem
A population consists of 500 elements. We want to draw a simple random sample of 50 elements from this population. On the first selection, the probability of an element being selected is
0.002
A measure of the average value of a random variable is called a(n)
expected value
A graphical presentation of a frequency distribution, relative frequency distribution, or percent frequency distribution of quantitative data constructed by placing the class intervals on the horizontal axis and the frequencies on the vertical axis is a
histogram
It is known that the population variance equals 484. With a 0.95 probability, the sample size that needs to be taken to estimate the population mean if the desired margin of error is 5 or less is
75
In hypothesis testing, the alternative hypothesis is
the hypothesis concluded to be true if the null hypothesis is rejected
Exhibit 8-1
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.
R
0.133
If the mean of a normal distribution is negative,
None of the alternative answers is correct.
Data collected at the same, or approximately the same, point in time are
cross-sectional data
A one-tailed test is a
hypothesis test in which rejection region is in one tail of the sampling distribution
When the data are labels or names used to identify an attribute of the elements and the rank of the data is meaningful, the variable has which scale of measurement?
ordinal
The weights (in pounds) of a sample of 36 individuals were recorded and the following statistics were calculated
mean = 160 range = 60
mode = 165 variance = 324
median = 170
The coefficient of variation equals
11.25%
In a sample of 800 students in a university, 160, or 20%, are Business majors. Based on the above information, the school's paper reported that "20% of all the students at the university are Business majors." This report is an example of
descriptive statistics
A graphical device for presenting qualitative data summaries based on subdivision of a circle into sectors that correspond to the relative frequency for each class is a
bar graph
Experimental outcomes that are based on measurement scales such as time, weight, and distance can be described by __________ random variables.
?
Exhibit 10-5
The following information was obtained from matched samples.
Individual Method 1 Method 2
1 7 5
2 5 9
3 6 8
4 7 7
5 5 6
Refer to Exhibit 10-5. The 95% confidence interval for the difference between the two population means is
-2.58 to 1.48
The difference between the largest and the smallest data values is the
Range
Exhibit 2-2
Information on the type of industry is provided for a sample of 50 Fortune 500 companies.
Industry Type Frequency
Banking 7
Consumer Products 15 Electronics 10
Retail 18
Refer to Exhibit 2-2. The percent frequency of industries that are classi
?
From a population of 200 elements, the standard deviation is known to be 14. A sample of 49 elements is selected. It is determined that the sample mean is 56. The standard error of the mean is
less than 2
You are given the following information about y and x.
y x
Dependent Independent
Variable Variable
5 15
7 12
9 10
11 7
Refer to Exhibit 12-2. The least squares estimate of b1 equals
-7.647
The weights (in pounds) of a sample of 36 individuals were recorded and the following statistics were calculated
mean = 160 range = 60
mode = 165 variance = 324
median = 170
The coefficient of variation equals
11.25%
A least squares regression line
?
If all the points of a scatter diagram lie on the least squares regression line, then the coefficient of determination for these variables based on this data is
could be 1 or -1
Statistical inference
?
In a crosstabulation
?
The equation that describes how the dependent variable (y) is related to the independent variable (x) is called
regression model
The interquartile range is the difference between the
highest and lowest value
A simple random sample from a process (an infinite population) is a sample selected such that
each element is selected independently
The difference between the lower class limits of adjacent classes provides the
class width
Excel's __________ function can be used to compute the sample correlation coefficient.
Correl
Exhibit 10-2
The following information was obtained from matched samples.
The daily production rates for a sample of workers before and after a training program are shown below.
Worker Before After
1 20 22
2 25 23
3 27 27
4 23 20
5 22 25
6 20 19
7 17 18
R
accept null hypothesis.
The value of the sum of the squared deviations from the mean, i.e., must always be
at least zero
Exhibit 8-2
The manager of a grocery store has taken 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 one minute.
Refer t
?
Generally, which one of the following is the least appropriate measure of central tendency for a data set that contains outliers?
?
If we want to provide a 95% confidence interval for the mean of a population, the confidence coefficient is
0.95
The function that defines the probability distribution of any continuous random variable is a
?
Exhibit 3-1
A researcher has collected the following sample data.
5 12 6 8 5
6 7 5 12 4
Refer to Exhibit 3-1. The 75th percentile is
?
A control chart that is used when the output of a production process is measured in terms of the proportion defective is
a P chart
A tabular summary of data showing the percentage of items in each of several nonoverlapping classes is a
percent frequency distribution
When the p-value is used for hypothesis testing, the null hypothesis is rejected if
the p-value is less than or equal to "alpha
Exhibit 10-5
The following information was obtained from matched samples.
Individual Method 1 Method 2
1 7 5
2 5 9
3 6 8
4 7 7
5 5 6
Refer to Exhibit 10-5. If the null hypothesis is tested at the 5% level, the null hypothesis
should not be rejected
Exhibit 3-2
A researcher has collected the following sample data. The mean of the sample is 5.
3 5 12 3 2
Refer to Exhibit 3-2. The interquartile range is
2
Exhibit 3-2
A researcher has collected the following sample data. The mean of the sample is 5.
3 5 12 3 2
Refer to Exhibit 3-2. The coefficient of variation is
81.24%
When the data have the properties of ordinal data and the interval between observations is expressed in terms of a fixed unit of measure, the variable has which scale of measurement?
?
Z is a standard normal random variable. The P(1.05 � z � 2.13) equals
0.1303
The manager of an automobile dealership is considering a new bonus plan in order to increase sales. Currently, the mean sales rate per salesperson is five automobiles per month. The correct set of hypotheses for testing the effect of the bonus plan is
Ho: u<= 5, Ha: u>5