Answer:
25 more boxes is needed
Step-by-step explanation:
12000 batteries require 50 boxes. Let's find the unit rate.
That is, how many batteries are in each box??
That's 12,000/50!
12,000/50 = 240 batteries per box
Now, to find how many boxes we would need for 18,000 batteries, we will have to divide the total (18000) by 240(number of batteries per box). That is:
18,000/240 = 75 boxes
We would need 75 boxes to pack 18,000 batteries.
We want "how many MORE boxes needed", so we will the excess:
75 - 50 = 25 more boxes is needed
To answer this we would need the expressions given.
Answer:
a) P-value = 0.0968
b) P-value = 0.2207
c) P-value = 0.0239
d) P-value = 0.0040
e) P-value = 0.5636
Step-by-step explanation:
As the hypothesis are defined with a ">" sign, instead of an "≠", the test is right-tailed.
For this type of test, the P-value is defined as:

being z* the value for each test statistic.
The probability P is calculated from the standard normal distribution.
Then, we can calculate for each case:
(a) 1.30

(b) 0.77

(c) 1.98

(d) 2.65

(e) −0.16

Answer:
The standard deviation of car age is 2.17 years.
Step-by-step explanation:
The Empirical Rule states that, for a normally distributed random variable:
68% of the measures are within 1 standard deviation of the mean.
95% of the measures are within 2 standard deviation of the mean.
99.7% of the measures are within 3 standard deviations of the mean.
In this problem, we have that:
Mean = 7.5
(a) If 99.7% of the ages are between 1 year and 14 years, what is the standard deviation of car age?
This means that 1 is 3 standard deviations below the mean and 14 is 3 standard deviations above the mean.
So

I want to find 



The standard deviation of car age is 2.17 years.
C:t=2:3
t:h=2:1
multiply first equation by 2 and 2nd by 3
c:t=4:6
t:h=6:3
so
c:t:h=4:6:3
if t is 4 more than c
t is 6 units and c is 4
6-4=2
so 4=2 units
2=1 unit
hollly is 3 units
3*2=6
holly has 6 cards