Answer:
The 80% confidence interval for the mean number of toys purchased each year is between 7.5 and 7.7 toys.
Step-by-step explanation:
We have that to find our 
level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of 
.
That is z with a pvalue of 
, so Z = 1.28.
Now, find the margin of error M as such
In which 
is the standard deviation of the population and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 7.6 - 0.1 = 7.5
The upper end of the interval is the sample mean added to M. So it is 7.6 + 0.1 = 7.7
The 80% confidence interval for the mean number of toys purchased each year is between 7.5 and 7.7 toys.
Make use of prime factorizations:
Both terms have a common factor of 
:
- - -
The second one is not true! We can write
Both terms have a common factor of 
:
Since 
, and 
, we'd still have to show that 
is a multiple of 6. This is impossible, because 
and there is no multiple of 2 that can be factored out.
Answer:
y = -0.85 + 0.09x; $49.82
Step-by-step explanation:
1. Calculate Σx, Σy, Σxy, and Σx²
The calculation is tedious but not difficult.
2. Calculate the coefficients in the regression equation
To two decimal places, the regression equation is
y = -0.85 + 0.09x
3. Prediction
If x = 563,
y = -0.85 + 0.09x = -0.85 + 0.09 × 563 = -0.85 + 50.67 = $49.82
(If we don't round the regression equation to two decimal places, the predicted value is $50.56.)
She will have $2118 in her account after five years
<h3>How to determine the amount in five years?</h3>
The given parameters about the compound interest are
Principal Amount, P = $1,900
Interest Rate, R = 2.2%
Time, t = 5
Compound interests are different from simple interest, and they are calculated using the following compound interest formula
CI = P(1 + R)^t - P
To calculate the amount, we have:
A = P + CI
So, the equation becomes
A = P + P(1 + R)^t - P
Evaluate the like terms
A = P(1 + R)^t
Substitute the known values in the above equation
A = 1900 * (1 + 2.2%)^5
Express 2.2% as decimal
A = 1900 * (1 + 0.022)^5
Evaluate the sum
A = 1900 * (1.022)^5
Evaluate the exponent
A = 1900 * 1.11495
Evaluate the product
A = 2118
Hence, she will have $2118 in her account after five years
Read more about compound interest at:
brainly.com/question/24924853
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