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江西财经大学2009-2010第一学期《统计学》期末考试试卷
Ⅰ、SINGLE CHOICE (1′×10＝10′)
1. After the price reduces, similarly RMB may buy commodity 15% more than before, asks the price index ( )
A.100% B.115% C.-13.04% D.86.96%。
2. In sampling with replacement, what will happen to the sample size if sampling average error decreases 25%? ( )
A. expands to times of the original
B. expands to times of the original
C. expands to times of the original
D. expands to times of the original
3.In the regression model ， reflects ( )
A. the linear change of y caused by the change of x
B. the linear change of x caused by the change of y
C. the effect of random factors to y except the linear relation of x and y
D. the effect of the linear relation of x and y
4. Simple sampling n=50 randomly from a population which the mean is 200, the standard deviation is 10, the expectation and variance of the sample’s mean are ( )
A. 200 and 0.2 B. 200 and 2
C. 20 and 1.4 D. 20 and 2
5. The estimate value of the slope of the regression line is 1.5, and the center of the samples is (4, 8), the equation of the regression line is ( )
A. =1.5x＋4 B. =1.5x+5
C. =1.5x+2 D. =2x+1.5
6. Compare stratified sampling and other sampling methods, when the sample size is equal, the sampling error of stratified is ( )
A. larger B. smaller
C. be equal D. reverse
7. Suppose you are doing an interval estimate of a population rate, the data of population is unknown; the variance of the rate has no data, and can’t calculate by the sample. Now, the variance should be valued by ( )
A. 50% B. 35%
C. 30% D. 25%
8. Which regression equation is confirm wrong ( )?
A. r=0.88
B. r=0.55
C. r=0.90
D. r=0.83
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