Recipricol the -1/2 to 2 and change the sign to multiply
-2/3 x 2 = -4/3
-4/3 = -1 1/3
-1 1/3 is your answer
hope this helps
Given:
Sample mean = 65.4
Standard deviation = 1.2
Sample size = 45
Confidence level = 99%
To find:
The confidence interval.
Solution:
The formula for confidence interval is
where, 
is sample mean, z* is confidence value, s is standard deviation and n is sample size.
Confidence value or z-value at 99% = 2.58
Putting the given in the above formula, we get
Therefore, the correct option is D.
The experimental probability that the high temp will be below 45 F on the 29th day is, 4.5 out of 29 days, that is because 20 of the days have had lower temperatures, so they left 9 days of and from those 9 days, they could be lower or greater that 45F (50% each side), that is:
4.5/29 = 0.155 = 15.5%
that is the exp probability
Part A
The exponential model that describes the situation
The formula is
Y (x)=400 (1+0.02/4)^4x
Y (x)=400 (1+0.005)^4x
Y (x)=400 (1.005)^4x
Where x is the number of years
Part B
The value of the account after 5 years
Y (5)=400×(1.005)^(4×5)
Y (5)=441.96
