To solve this problem, you'd want to start by finding the mean of the given numbers. To find the mean, add all the numbers together and divide by how many there are.
Next, you'll see that the question says one of the rents changes from $1130 to $930. So find the mean of all the numbers again, except include $930 in your calculation instead of $1130.
I got $990 as the mean for the given numbers, and $970 as the mean after replacing the $1130 with $930. Subtracting the two means gives you $20. So the mean decreased by $20.
Now for the median, all you need to do is find the median of the given numbers and compare them with the median of the new data. Because there are ten terms, you have to add the middle two numbers and divide by two. $990 + $1020 = 2010. 2010÷2 = $1005 as the first median.
The new rent is 930, so you have to reorder the data so it goes from least to greatest again. 745, 915, 925, 930, 965, 990, 1020, 1040, 1050, 1120. After finding the median again you get 977.5. Subtracting the two medians gives you $27.5 as how much the median decreased. Hope this helps!
Use the table of Z-score, considering it represnts the probability of data to the left of Z-value, the needed probability would be the subtraction of Z -0.3 to Z -1.32 value.
