# Stats - Coding

How would a mean height change if everyone stood on chairs?

It would increase by the height of the chairs.

How would a standard deviation for height change if everyone stood on chairs?

It would not change.

How would a mean height change if everyone was 3 times taller?

It would be 3 times bigger.

How would a standard deviation for height change if everyone was 3 times taller?

It would be 3 times bigger.

How would a variance for height change if everyone was 3 times taller?

It would be 9 times bigger.

Why do we use coding?

In order to transform our data into something that can be worked with more easily.

Once you’ve used coding to transform data and calculate values, what must you do?

Convert the values back.

In a measurement of heights $h$, the values are coded by subtracting $2$ and dividing by $3$. How could you write the new heights $c$?

What is the general coding formula?

If $y = \frac{x - a}{b}$, then what is $\overline{y}$?

If $y = \frac{x - a}{b}$, then what is $\sigma _ y$?

In the context of coding, what is $a$ and $b$ in $y = \frac{x - 1000}{10}$?

- $a = 1000$
- $b = 10$

Before coding $\overline{x} = 11$. After using $y = \frac{x + 10}{3}$, what is $\overline{y}$?

$7$.

After coding using $y = 3x - 20$, the $\sigma _ y$ was $12$. What was the original $\sigma _ x$?

$4$.