Answer:
Step-by-step explanation:
To factor an expression you have to first find the highest common factor (HCF) of the numbers in the expression. You divide them by their HCF, bracket it and place the HCF outside the bracket.
To check if it is factored properly you can do the opposite of what you just did by clearing the bracket.
9 (7 + 9)
(9 x 7) + (9 x 9)
= 63 + 81
Answer:
Decision: Support the null hypothesis.
Sample mean: -12
Step-by-step explanation:
Hello!
When deciding with a Confidence interval you have to keep in mind that the following conditions are met:
H₀: μ₁ - μ₂= 0
H₁: μ₁ - μ₂≠ 0
α: 0.05
If the interval contains the cero, it means that there is no difference between the means, so you support the null hypothesis.
If the interval doesn't contain the cero, there is a difference between the two means, so you reject the null hypothesis.
The intervals to estimate the population mean have the following structure:
Estimator ± Margin of error
This means that the sample mean (point estimate of the population mean) is in the middle of the calculated interval. To know it's the value you have to do a simple calculation:
sample mean:
sample mean:
sample mean: -12
I hope it helps!