1. The diameter of a spindle in a small motor is supposed to be 5 mm. If the spindle is either too small or too large, the motor will not work properly. The manufacturer measures the diameter in a sample of motors to determine whether the mean diameter has moved away from the target. What are the null and alternative hypotheses (H0 = null hypothesis and Ha = alternative hypothesis)?
A.H0: Mean= 5 and Ha: Mean is not equal to 5
B.H0: Mean = 5 and Ha: Mean <5
C.H0: Mean < 5 and Ha: Mean > 5
D.H0: Mean = 5 and Ha: Mean > 5
2. The correlation between two variables is -0.63 for a sample of 20 observations. What is the coefficient of determination between the two variables?
A.0.63
B.0.3969
C.0 .7937
D.None of the above.
3. In simple linear correlation analysis
A.We consider several dependent variables.
B.We study the strength of the association between two variables.
C.We consider the intercept with the Y-axis.
D.None of the above.
4. The sample correlation coefficient
A.Has the same sign as the slope, i.e. b.
B.Can range from -1.00 up to 1.00
C.Is also called Pearson's r.
D.All of the above.