Answer:
CI = 29.8 ± 3.53
Critical value is z = 2.58
Step-by-step explanation:
First of all let's find margin of error. It is given by the formula;
ME = zσ/√n
We are given;
Standard deviation; σ = 3.62
Sample size; n = 7
Mean; x¯ = 29.8
Now, z-value for 99% Confidence level is 2.58
Thus;
ME = (2.58 × 3.62)/√7
ME = 3.53
CI is written as;
CI = x¯ ± ME
CI = 29.8 ± 3.53
Critical value is z = 2.58
Answer:
20
Step-by-step explanation:
→ First find the value of x and y
x + y = 5
x - y = 4
→ Add the equations to cancel out the y's
2x = 9
→ Divide both sides by 2 to find the value of x
x = 4.5
→ Substitute x = 4.5 back into x - y = 4 to find the value of y
4.5 - y = 4
→ Minus 4.5 from both sides to isolate -y
-y = -0.5
→ Multiply everything by -1
y = 0.5
→ Substitute x = 4.5 and y = 0.5 into x² - y²
4.5² - 0.5² = 20.25 - 0.25 = 20
Is something missing
???????????????????//
