Descriptive statistics deals with methods of（）

单项选择题Simon Arnett, Director of Human Resources, is exploring the causes of employee absenteeism at Buderim Bottling during the last operating year (1 January 2005 to 31 December 2005). Personnel records of 50 employees are selected for analysis. (The plant employs 250.) For this study, the average number days absent for these 50 employees is a （）.

A.population
B.sample
C.parameter
D.statistic

单项选择题A summary measure that is computed from a sample to describe a characteristic of the population is called（）

A.a parameter
B.a statistic
C.a population
D.Both A and C are correct，since they are the same

单项选择题Simon Arnett, Director of Human Resources, is exploring the causes of employee absenteeism at Buderim Bottling during the last operating year (1 January 2005 to 31 December 2005). The average number of absences per employee, calculated from the personnel data of all employees, is a （）.

A.population
B.sample
C.parameter
D.statistic

单项选择题A politician who is running for the office of premier in a state with 3 million registered voters commissions a survey. In the survey, 53.6% of the 5000 registered voters interviewed say they plan to vote for him. The population of interest is the（）

A.3 million registered voters in the state.
B.5000 registered voters interviewed.
C.53.6%of，or 2680，voters interviewed who plan to vote for him
D.46.4%of，or 2320，voters interviewed who plan not to vote for him

单项选择题Claudia Taylor, Director of Global Industrial Sales in Melbourne, is concerned by a deteriorating sales trend. Specifically, the number of customers is stable at 1500 but they are purchasing less each year. She orders her staff to search for causes of the downward trend by selecting a focus group of 40 industrial customers. For this study, the set of 40 industrial customers is a （）.

A.statistic
B.sample
C.population
D.parameter

单项选择题Michael Bayley, Marketing Director of UniPower’s Electrical Division, is leading a study to identify and assess the relative importance of product features. Michael directs his staff to design a survey questionnaire for distribution to all of UniPower’s 954 customers. For this study, the set of 954 customers is a （）.

A.statistic
B.population
C.parameter
D.sample

单项选择题Penny Bauer, Chief Financial Officer of Harrison Haulage, suspects irregularities in the payroll system, and orders an inspection of ‘each and every payroll voucher issued since 1 January 2005’. Five per cent of the payroll vouchers contained material errors. This is an example of （）.

A.nonparametric statistics
B.nominal data
C.descriptive statistics
D.inferential statistics

单项选择题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

单项选择题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

单项选择题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.