Answer:
240 12.5p + 65
14 p
Step-by-step explanation:
I'll explain the equation in different parts
12.5p - Since the number of times he visits is unknown, it has to be a variable. With each visit, however, he earns 12.5 points.
65 - This is a set value that remains constant
240 - Since he needs AT LEAST 240 points, he needs 240 points or more to get his free ticket
As for solving the equation just use properties of equality
240 12.5p + 65
175 12.5p
14 p
Answer:
a)
And we can find this probability with this difference and with the normal standard table or excel:
b)
And we can use the z score defined by:
And using the limits we got:
And we want to find this probability:
Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Part a
Let X the random variable that represent the resitances of a population, and for this case we know the distribution for X is given by:
Where and
We are interested on this probability
And the best way to solve this problem is using the normal standard distribution and the z score given by:
If we apply this formula to our probability we got this:
And we can find this probability with this difference and with the normal standard table or excel:
Part b
We select a sample size of n =4. And since the distribution for X is normal then we know that the distribution for the sample mean is given by:
And we want this probability:
And we can use the z score defined by:
And using the limits we got:
And we want to find this probability: