Question

he number of years before a Sunshine CD player breaks down is normally distributed with a mean of 4.1 years and a standard deviation of 1.3 years.



Part A

Which of the graphs below represents the situation?

A


B


C


D

Answer 1

I can’t see the four graphs — could you either upload them or describe each one (where the peak is, whether it’s symmetric/skewed, any shading, and the x-axis tick marks)?

To pick the correct graph yourself, check these things:

- It should be a symmetric bell-shaped (normal) curve centered at the mean 4.1.
- The inflection points (where the curve changes concavity) should be at mean ± 1 sd → 4.1 ± 1.3 → about 2.8 and 5.4.
- The bulk of the distribution (±3 sd) lies between 4.1 ± 3.9 → about 0.2 and 8.0, so the curve should be essentially zero well before negative x and near 8.
- It should not be skewed left or right.

If any graphs show those features, that one is correct. If you post the images or describe them I’ll pick which letter (A–D) matches.