Answer:
60 miles per hour
Step-by-step explanation:
First, put the equation in a fraction.
You would put 180 up top because people always say miles per hour not the other way around.
You can see the dividing line as your "per" and your "hour" would be the bottom number.
To find the unit rate, you will divide the numerator (180) and the denominator (3).
Your final answer should be 60 miles per hour.
Answer:
For a mean oil change time of 20.51 minutes there would be a 10% chance of being at or below
Step-by-step explanation:
To solve this question, we need to understand the normal probability distribution and the central limit theorem.
Normal probability distribution
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean and standard deviation
, the zscore of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
Central Limit Theorem
The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean and standard deviation
, the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean
and standard deviation
.
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
In this problem, we have that:
Treating this as a random sample, at what mean oil-change time would there be a 10% chance of being at or below?
This is the 10th percentile, which is X when Z has a pvalue of 0.1. So it is X when Z = -1.28.
By the Central Limit Theorem
For a mean oil change time of 20.51 minutes there would be a 10% chance of being at or below