Given that the mean is 55 inches and Dave is 57 inches, he would have increased the mean of the height in the stem-and-leaf plot that the students were making. This is however is also dependent upon the central tendency that was used, in this case the central tendency is mean or average.
Answer:
a. 12
b. 7.200 and 2.683
Step-by-step explanation:
The computation is shown below:
Given that
P = 0.40 and n = 30
a)
The expected value of received e-mails is
= n × p
= 30 × 0.4
= 12
b)
The variance of emails received is
= n × p × (1 - p)
= 30 × 0.4 × 0.6
= 7.200
Now
The standard deviation of emails received is
= sqrt(variance)
= 2.683
We simply applied the above formula
Answer:
B
Step-by-step explanation:
Solve
hmmm
half life
well, 120 to 60 is half
60=120e^(-0.00043t)
solve for t
divide both sides by 120
1/2=e^(-0.00043t)
take ln of both sides
ln(1/2)=-0.00043t
divide both sides by -0.00043
ln(1/2)/-0.00043=t
t≈1611.97 years
about 1612 years