The price of an item yesterday was $120.today the price fell to $78 find the percentage decrease

To find percentage decrease, we need to see how "much" of 120 was taken off.

So, let's call the percentage x (the percentage in decimal form).

120 * x = 78

so,

78/120 = x

.65 = x

So, our percentage in decimal form is .65, to get it to an actual percentage, we multiply it by 100 (since a percentage is out of 100)

The percentage decrease is 65%

A. R2 = 0.6724, meaning 67.24% of the total variation in test scores can be explained by the least‑squares regression line.

Step-by-step explanation:

John is predicting test scores of students on the basis of their home work averages and he get the following regression equation

y=0.2 x +82.

Here, dependent variable y is the test scores and independent variable x is home averages because test scores are predicted on the basis of home work averages.

The coefficient of determination R² indicates the explained variability of dependent variable due to its linear relationship with independent variable.

We are given that correlation coefficient r= 0.82.

coefficient of determination R²=0.82²=0.6724 or 67.24%.

Thus, we can say that 67.24% of total variability in test scores is explained by its linear relationship with homework averages.

Also, we can say that, R2 = 0.6724, meaning 67.24% of the total variation in test scores can be explained by the least‑squares regression line.