Research is conducted to determine if there is any relationship between obesity and the number of hours per day children spend in front of a video screen. A group of 13 year old children were surveyed and the average results are tabulated below. Calculate the correlation coefficient and comment on it’s value.
Hours (H) | 0.5 | 1 | 1.5 | 2 | 2.5 | 3 | 3.5 | 4 | 4.5 |
Weight above average (W) |
0.50 | 1.00 | 1.25 | 1.85 | 2.20 | 2.50 | 3.20 | 3.40 | 3.65 |
enter calculator mode: Mode Stat We need option: A + Bx or 2 variable (depending on your calculator)
enter your first row of data into the x column enter the second row of data into the y column press
Press AC
Press shift 1 [STAT]
select the r option
r = 0.995
since r is almost 1, and positive, then there is a very strong positive correlation between H and W