Answer:
The number of observations required is closest to 609 ⇒ b
Step-by-step explanation:
The formula of the sample size is n = [( . σ)/E]² , where
- σ is the standard deviation
- E is the margin of error
- is the z-score, where 1 - α = confidence interval
∵ We want 90% confidence interval for the average amount
spent on books by freshmen in their first year at a major
university
∴ 1 - α = 90%
∵ 90% = 90 ÷ 100 = 0.90
∴ 1 - α = 0.90
- Subtract 1 from both sides
∴ - α = -0.10
- Divide both sides by -1
∴ α = 0.10
- Find the value of
∴ = = 0.05
- Look to the normal distribution table to find z-score for this
value with opposite sign
∴ = 1.645
∵ The interval is to have a margin of error of $2
∴ E = 2
∵ We estimate that the standard deviation of the amount spent
will be close to $30
∴ σ = 30
- Substitute these values in the formula above
∴ n = [(1.645)(30) ÷ 2]²
∴ n = 608.855
- Round it to the whole number
∴ n = 609
The number of observations required is closest to 609
Answer:
Graph C
Step-by-step explanation:
Answer:
l=14 yards and w=5 yards
Step-by-step explanation:
Let the width be w units, then the length of the rectangle is:
The area of the rectangle is given as 79 square yards.
This implies that:
Expand:
O
We factor to get:
Since we are talking about length, we have width equal 5 yards.
The length is:
Answer:
Let x be the number.
It is given that a 15 : 9 aspect ratio and a screen that is 42 inches.
Aspect ratio states that the ratio of the display image’s width to its height.
Then;
Width of the television of(w) = 15x
and height of the television(h) = 9x.
Since, television is in the form of Rectangle.
And it is also, given that the screen is 42 inches .
⇒Diagonal of the television(D) = 42 inches
Using formula of diagonal of the rectangle :
Substitute the given values to solve for x;
or
Then:
width of the television (15x) = 15(2.4) = 36 inches and
Height of the television (9x) = 9(2.4) = 21.6 inches.
Therefore, the actual dimensions of the television are;
width = 36 inches and height = 21.6 inches.