智慧树知到《商务统计》2023见面课答案

智慧树知到《商务统计》2023见面课答案
1、 One rule that must always be followed in constructing frequency distributions is that __.
A.adjacent classes must not overlap
B.the midpoint of each class must be a whole number
C.the width of each class is equal to the range
D.the number of intervals must be an odd number
正确答案：adjacent classes must not overlap
2、A.are established correctly
B.are not mutually exclusively
C.are not collectively exhaustive
D.don not reference a population parameter
正确答案：are not collectively exhaustive
3、When a false null hypothesis is not rejected, the researcher has made a
A. type II error.
B. sampling error.
C.powerful error.
D. type I error
正确答案： type II error.
4、A.
B.
C.
D.
正确答案：
5、Which of the following is an appropriate null hypothesis?
A.
B.
C.
D.
正确答案：
6、In what type of test is the variable of interest the difference between the values of the observations rather than the observations themselves?
A.a test for the equality of variances from 2 independent populations
B.a test for the difference between the means of 2 related populations
C.a test for the difference between the means of 2 independent populations
D.All of the above
正确答案：All of the above
7、The test for the equality of two population variances is based on the
A.ratio of the two sample variances
B.difference between the two sample variances
C.difference between the two population variances
D.difference between the sample variances divided by the difference between the sample means
正确答案：ratio of the two sample variances
8、A.zero.
B.-0.5.
C.0.5
D.one.
正确答案：0.5
9、A.t distribution with 73 degrees of freedom
B. t distribution with 72 degrees of freedom.
C.t distribution with 71 degrees of freedom
D. t distribution with 70 degrees of freedom.
正确答案： t distribution with 70 degrees of freedom.
10、A.
B.
C.
D.
正确答案：
1、Given the following information:Standard deviation = 8 Coefficient of variation = 64%The mean would then be
A.12.5
B. 8
C.0.64
D.1.25
正确答案：12.5
2、From a population of 500 elements, a sample of 225 elements is selected. It is known that the variance of the population is 900. The standard error of the mean is approximately
A.1.1022
B.2
C.30
D.1.4847
正确答案：1.4847
3、A sample of 400 observations will be taken from an infinite population. The population proportion equals 0.8. The probability that the sample proportion will be greater than 0.83 is
A.0.4332
B. 0.9332
C.0.0668
D. 0.5668
正确答案：0.0668
4、A weighted average of the value of a random variable, where the probability function provides weights is known as
A.a probability function
B. a random variable
C.the expected value
D.random function
正确答案：the expected value
5、The student body of a large university consists of 60% female students. A random sample of 8 students is selected. What is the probability that among the students in the sample exactly two are female?
A.0.0896
B.0.2936
C.0.0413
D.0.0007
正确答案：0.0413
6、A.1.431
B.2.047
C.3.05
D. 21
正确答案：1.431
7、Exhibit 2 The following represents the probability distribution for the daily demand of computers at a local store.
A.0.7
B.0.3
C.0.4
D.1.0
正确答案：0.7
8、 If A and B are independent events, then
A. P(A) must be equal to P(B)
B.P(A) must be greater than P(B)
C.P(A) must be less than P(B)
D.P(A) must be equal to P(A│B)
正确答案：P(A) must be equal to P(A│B)
9、The purpose of statistical inference is to provide information about the
A.sample based upon information contained in the population
B.population based upon information contained in the sample
C.population based upon information contained in the population
D.mean of the sample based upon the mean of the population
正确答案：population based upon information contained in the sample
10、A theorem that allows us to use the normal probability distribution to approximate the sampling distribution of sample means and sample proportions whenever the sample size is large is known as the
A.approximation theorem
B.normal probability theorem
C.central limit theorem
D.central normality theorem
正确答案：central limit theorem
1、If two variables, X and Y, have a strong linear relationship, then
A.There may or may not be any causal relationship between X and Y
B.X causes Y to happen
C.Y causes X to happen
D.None of these alternatives is correct
正确答案：There may or may not be any causal relationship between X and Y
2、In order to test for the significance of a regression model involving 14 independent variables and 255 observations, the numerator and denominator degrees of freedom (respectively) for the critical value of F are
A.14 and 255
B.255 and 14
C.14 and 240
D.13 and 240
正确答案：14 and 240
3、In a multiple regression analysis model involving 2 independent variables and 15 observations, SSR = 268 and SST = 325. The adjusted coefficient of determination is
A.0.90
B.0.80
C.0.70
D.Not enough information is provided to answer this question
正确答案：0.80
4、Which is considered to be a positive linear relationship
A.x goes up, y goes down
B.x goes down, y goes up
C.x goes down, y goes down
D.x goes up, y goes up
E.both c and d
正确答案：both c and d
5、In a regression analysis, if SSE is hypothetically decreased, then
A.R2 will Decrease
B.Se will Increase
C.SST will decrease
D.Both a and b
E.None of the above
正确答案：None of the above
1、deviation is the distance between a ___ and the ____.v
A.median, mean
B.data point, mean
C. quartile, median
D.data point, median
正确答案：data point, mean
2、The sum of the deviations may be 0.00. To get around this problem, we use the __ of the deviations
A. square
B.absolute value
C.minimum
D. maximum
正确答案： square
3、The reason that we prefer the sample standard deviation as our measure of typical variation instead of the sample variance is that _
A. the variance is not as accurate a measurement as the standard deviation
B.the standard deviation has been corrected for bias while the variance has not
C.the standard deviation is in the same units as the data values.
D.the variance is in the same units as the data values.
正确答案：the standard deviation is in the same units as the data values.
4、The empirical rule tells us that approximately of the values cluster within a distance of 1 standard deviation from the mean for a bell-shaped distribution
A.68%
B.95%
C.99.7%
D.none of the above
正确答案：68%
5、X is a discrete random variable that can have values from 0 to infinity, and occurrences of the events X counts are independent. The standard deviation of X is equal to the square root of the mean. The probability distribution of X is a(n) _____distribution.
A. binomial
B.uniform
C.normal
D.Possion
正确答案：Possion
6、 When analyzing categorical data, stem and leaf display is an appropriate plot.
A.正确
B.错误
正确答案：B
7、 If the population distribution is unknown, in most cases the sampling distribution of the mean can be approximated by the normal distribution if the sample size is at least 15 observations
A.正确
B.错误
正确答案：B
8、Statistical independence means the outcome of one event is independent of the outcome of a second event
A.正确
B.错误
正确答案：A