The probability that mean race time is less than 4.3 is 0.3534.
Using the parameters given ;
- Mean = 5.18
- standard deviation = 2.34
- score, x = 4.3
Firstly, we need to calculate the Zscore which corresponds to the given score of 4.3
- Zscore = (Score - Mean) / standard deviation
Now we have;
Zscore = (4.3 - 5.18) / 2.34
Zscore = -0.3761
Using the normal distribution table ; the probability for the zscore obtained is ;
P(Z < -0.3761) = 0.35342
Therefore, the probability is 0.3534.
Complete Question
A course for a snail race has times that are skewed right with a mean of 5. 18 minutes and a standard deviation of 2. 34 minutes. If a random sample of 38 snails is selected, what is the probability that the mean race time is less than 4. 3 minutes? 0. 0102 0. 3534 0. 6466 0. 9098