In: Statistics and Probability
A survey of prices for external disk drives found the accompanying data, where 1 TB equals 1000 gigabytes. Some research on the prices discovered that the 160 GB hard drive was a special "hardened" drive designed to resist physical shocks. Because it is completely different from the other drives, it was removed from the data. The correlation is now 0.994 and other summary statistics are shown in the accompanying popup window. Complete parts a and b.
a) If a drive has a capacity of 2.8464 TB (or 1 SD above the mean of 1.259 TB), how many standard deviations above or below the mean price of $157.32 do you expect the drive to cost?
The expected cost is _________, standard deviations __above or below__ the mean price.
b) To what price does that correspond?
$ _______ ( Round to the nearest cent as needed.)
Capacity (in TB) | Price (in $) |
0.090 | 19.00 |
0.120 | 34.49 |
0.210 | 223.45 |
0.250 | 44.99 |
0.350 | 52.99 |
1.0 | 161.00 |
3.0 | 355.79 |
4.0 | 433.00 |
Capacity (in TB) / Price (in $)
x= 1.259 / y= 157.32
SD (x) = 1.5874 / SD(y) = 169.87
zx = (x-xbar)/sx
zx = (2.8464-1.259)/1.5874
zx = 1(which was given in the question)
zyhat = r * zx
zyhat = .995 * 1
zyhat = 0.995