Cell phone production engineers have noticed that among a group of 138 customers aged 14-23 who send more text messages tend to use a higher percentage of their phone’s memory.
Answer
A
Explanatory variable: age of customerResponse variable: percentage of phone memory used
B
Explanatory variable: percentage of phone memory usedResponse variable: age of customer
C
Explanatory variable: number of text messages sentResponse variable: percentage of phone memory used
D
Explanatory variable: percentage of phone memory usedResponse variable: number of text messages sent