34.7 Quick review questions

A study of Chinese paedatric patients (Wong et al. 2018) studied the relationship between the 6-minute walk distance (6MWD) and maximum oxygen uptake (VO2_max) for $n=29$ patients. The correlation coefficient is reported as $r=0.457$, and the corresponding $P$-value as $P=0.013$.

1. The $x$-variable is
   6-minute walk distance Maximum oxygen uptake
2. True or false: Since the $P$-value is small, the correlation must be quite strong.
   TRUE FALSE
3. The relationship is best described as
   Negative Positive
4. The value of $R^2$ (to one decimal place, expressed as a percentage) is:
   
5. For statistical validity, we need to assume that:
   The response variable has a normal distribution The explanatory variable has a normal distribution The sample size is larger than 25 A linear relationship exists between the variables