The confidence interval formula is computed by:
Xbar ± Z s/ sqrt (n)
Where:
Xbar is the mean
Z is the z value
S is the standard deviation
N is the number of samples
So our given are:
90% confidence interval with a z value of 1.645
Sample size 40, 45
Mean 180, 179
Standard deviation 2, 4
So plugging that information in the data will give us a
confidence interval:
For 1:
Xbar ± Z s/ sqrt (n)
= 180 ± 1.645 (2 / sqrt (40))
= 180 ± 1.645 (0.316227766)
= 180 ± 0.520194675
= 179.48, 180.52
For 2:
Xbar ± Z s/ sqrt (n)
= 179 ± 1.645 (4 / sqrt (45))
<span>= 179 ± 1.645 (0.596284794)</span>
therefore, the answer is letter b
lateral surface area of cylinder is = 2πrh
= 2 × 3.14 × 8 ×5
= 251.2 unit²
HOPE IT HELPS
PLEASE MARK ME BRAINLIEST ☺️
She was late 7 times. $42-$10=$32. $32/8 = 4. The first 3 days she was late plus the other 4 times being late that month is 7 days late.
1a) Firstly, lets start by expanding the brackets. x × x is x². So x(x+1) = x² + x. Then we do the second part. 2 × x = 2x and 2 × 1 = 2. Now we have
x² + 3x + 2.
Now what we do is simplify through quadratic formula. We look at the last digit which is 2. What two numbers multiplies to give you 2? 2 and 1. 2 x 1 = 2 and 2 + 1 = 3. Our second number is 3 so this is the right amount. so now we just put the two factors together. (x + 1)(x+2). This is the answer.
b) I have explained above and so am just gonna write the answers. After expanding we get x² + 2x + 1. We get simplify to
= (x + 1)(x+1)
c) y² + 3y + 4. This cannot be simplified into the format so we leave it like this.
d) = 0.
Have a go at the last ones by yourself, if you still need help, I am available!
