Starter

1. Starter The weights of newborn lambs on a farm are normally distributed with a mean of 2.4kg and a standard deviation of 200g.

2. What is the probability that a randomly chosen lambs weight is between 2kg and 2.5kg? What is the probability that a randomly chosen lamb is greater than 2.65kg? 4% of newborn lambs are too small to survive the cold winter temperatures on the farm. What is the minimum weight of a newborn lamb that will survive?

3. Note 11: Inverse Normal - Excellence We need to find an unknown mean or standard deviation, using the formula Z = X – μ σ Using the relevant z-score and μ = 0 and σ = 1

4. Example: Weights of a certain type of carrot are normally distributed with standard deviation 5g. 3% are packed as ‘baby carrots’ because they are below 30g in weight. What is the mean weight of this type of carrot?

5. P(X < 30 ) =0.03 0.03 30 μ Z= -1.881 Z = X – μ σ -1.881 = 30 – μ 5 Μ = 39.4g Calculator – Inverse Normal New Calculator – Tail Left Area = 0.03 Std dev = 1 Mean = 0

6. Exercises : NuLake Page 31 - 34