Statistics 8th Edition Jia Junping Chapter 1 after class exercises and answers summary

One 、 Exercises

1 Indicate the types of the following variables .
（1） Age .
（2） Gender .
（3） Automobile output .
（4） Employees' attitude towards a reform measure of the enterprise （ In favor of 、 neutral 、 against ）.
（5） How to pay for goods （ cash 、 The credit card 、 Check ）.

answer ： Variables can be divided into ： Categorical variables 、 Sequential variables and numerical variables .（2）（5） It belongs to classification variable ;（4） It belongs to sequence variable ;（1）（3） It belongs to numerical variable .

2 A research department is preparing to extract 2000 The annual per capita income of all working families in the city is inferred from working families . requirement ：
（1） Describe the population and sample .
（2） Point out parameters and statistics .

answer ：（1） In general “ All the working families in the city ”, The sample is “ Extraction of 2000 Working families ”.
（2） Parameter is “ The annual per capita income of all working families in the city ”, The statistics are “ Extraction of 2000 The annual per capita income calculated by families ”.

3 A research institution from IT Randomly selected from practitioners 1000 People were investigated as samples , among 60% Answer that their monthly income is 15000 Yuan of above ,50% Percent of the people answered that their consumption payment method is to use credit card .
Answer the following questions ：
（1） What is the overall purpose of this study ？
（2） Monthly income is a categorical variable 、 Sequential variable or numerical variable ？
（3） Consumption payment method is a categorical variable 、 Sequential variable or numerical variable ？
（4） This research involves cross-sectional data or time series data ？

answer ：（1） In general “ all IT practitioners ”;
（2） Monthly income is a numerical variable ;
（3） Consumption payment method is a categorical variable ;
（4） This study involves cross-sectional data .

4 A survey shows that , The average monthly cost of online shopping is 2000 element , The main reason why they choose to shop online is “ Cheapness ”.
Answer the following questions ：
（1） What is the overall purpose of this study ？
（2）“ The reason why consumers shop online ” It's a categorical variable 、 Sequential variable or numerical variable ？
（3） What parameters do researchers care about ？
（4）“ The average monthly cost of online shopping is 2000 element ” Is it a parameter or a statistic ？
（5） Researchers mainly use descriptive statistical methods or inferential statistical methods ？

answer ：（1） The overall purpose of this study is “ All online shoppers ”;（2）“ The reason why consumers shop online ” It's a categorical variable ;
（3） The parameters concerned by researchers are “ The average monthly cost of all online shoppers ”;
（4）“ The average monthly cost of online shopping is 2000 element ” It's statistics ;
（5） Researchers mainly use inferential statistical methods .