Find the seven standardized values for each variable, and then their product. (round your answers to two decimal places.) temperature 29.74 29.93 30.07 30.22 30.55 30.67 30.92 growth 2.63 2.63 2.64 2.64 2.53 2.45 2.29 zx zy zxzy

To standardize the values, you need to subtract the mean and divide the result by the standard deviation.

... z = (x - μ)/σ

The mean, of course, is the sum of values divided by 7. The standard deviation is the square root of the quantity the mean of the squares minus the square of the mean.

μx = 212.10/7 = 30.30

σx = √(6427.7236/7 -30.30²) ≈ 0.3953

μy = 17.81/7 ≈ 2.5443

σy = √(45.4205/7 - 2.5443²) ≈ 0.1235

It is convenient to let a calculator or spreadsheet do these repetitive calculations. The attached table shows the zx, zy, and zxzy. The table uses t and g in place of x and y.