Answer:
1. the probability that giraffe will be shorter than 17 feet tall is equal to 0.1056
2. the probability that a randomly selected giraffe will be between 16 and 19 feet tall is equal to 0.8882
3. the the 90th percentile for the height of giraffes is 19.024
Step-by-step explanation:
To calculate the probability that a giraffe will be shorter than 17 feet tall, we need to standardize 17 feet as:
Where x is the height of the adult giraffe, m is the mean and s is the standard deviation, so 17 feet is equivalent to:
Now, the probability that giraffe will be shorter than 17 feet tall is equal to P(z<-1.25). Then, using the standard normal distribution table, we get that:
At the same way, 16 and 19 feet tall are equivalent to:
So, the probability that a randomly selected giraffe will be between 16 and 19 feet tall is equal to:
Finally, to find the the 90th percentile for the height of giraffes, we need to find the value z that satisfy:
Now, using the standard normal distribution table we get that z is equal to 1.28. Therefore, the height x of the giraffes that is equivalent to 1.28 is:
it means that the the 90th percentile for the height of giraffes is 19.024