Answer:
Amounts in the intervall
Step-by-step explanation:
We will take the variables c and s, where
c = amount to spend that month
s = savings of the month.
Since each month we save at least 100, we know that
Moreover, we earn $250 per month and we spend $20 in a kayaking club, which tells us that
and so
By multiplying by -1, the first inequality also tells us that
Consequently by adding 230 to the inequality, we get that
Answer:
And we can find this probability using the complement rule:
And using the normal standard distirbution table or excel we got:
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".
Solution to the problem
Let X the random variable that represent the variable if interest of a population, and for this case we know the distribution for X is given by:
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 using the complement rule:
And using the normal standard distirbution table or excel we got: