Originally Posted by

**Kiwigirl** I have a Probability question from about a year ago, involving the normal distribution, which I answered but I lost the paper my answer was on, until now. I have finally found it, but now that I'm looking over my answer from a year ago, I see that there are no formulas and certainly no normal distribution table to support my answer. Would someone please be able to help me with this? I need to know what the normal distribution table will look like to support my working and where to put the formulas into my equations.

**The normal distribution**

*Give clear explanations and show all working. You must provide a diagram and correct probability statements for the question. *

The weights of newborn babies in Battland are normally distributed with a mean of 3.43 kg and standard deviation of 0.36 kg.

1% of newborn babies are classed as low birthweight babies and often in need of special care. What weight is defined as low birthweight in Battland?

**Working:**

3.43 - (0.36 x 3)

= 2.35

2.35 - 3.43 divided by 0.6 = 0.4987

0.5 - 0.4987 = 0.0026

0.5 - 0.0026 = 0.4974

z = 2.79

0.36 x 2.79 = 1.0044

3.43 - 1.0044 = 2.4256

= 2.43

So, 2.43 kg is defined as low birthweight in Battland