Answer:

Step-by-step explanation:
<u>Confidence Interval</u>
When the population standard deviation
is known, the formula for a confidence interval for a population mean
is:

Where n is the sample size and z is the corresponding z-value from the standard normal distribution for the selected confidence level. The value of z for a 95% confidence interval is z=1.96. The rest of the values are

Calculating the confidence interval


Or, equivalently

Answer:
Y=168
Step-by-step explanation:
Y varies directly as X
Y=kx
K is a constant
28=k2
K=28/2 =14
Y=14x
Y=14×12
Y=168
Answer:
16 oranges
Step-by-step explanation:
The ratio of oranges to apples is 4:3 which means that for every four oranges, there are 3 apples.
Since there are 12 apples in the basket, to find the number of oranges, set up a ratio.
4/3 = x/12 (x represents the number of oranges)
Cross multiply.
48 = 3x
Divide by 3.
x = 16
There are 16 oranges in the basket.
Hope that helps.