Answer:
Yes, both np and n(1-p) are ≥ 10
Mean = 0.12 ; Standard deviation = 0.02004
Yes. There is a less than 5% chance of this happening by random variation. 0.034839
Step-by-step explanation:
Given that :
p = 12% = 0.12 ;
Sample size, n = 263
np = 263 * 0.12 = 31.56
n(1 - p) = 263(1 - 0.12) = 263 * 0.88 = 231.44
According to the central limit theorem, distribution of sample proportion approximately follow normal distribution with mean of p = 0.12 and standard deviation sqrt(p*(1 - p)/n) = sqrt (0.12 *0.88)/n = sqrt(0.0004015) = 0.02004
Z = (x - mean) / standard deviation
x = 22 / 263 = 0.08365
Z = (0.08365 - 0.12) / 0.02004
Z = −1.813872
Z = - 1.814
P(Z < −1.814) = 0.034839 (Z probability calculator)
Yes, it is unusual
0.034 < 0.05 (Hence, There is a less than 5% chance of this happening by random variation.
Alright, so we know that there are 7 days a week with 24 hours per day.
24x7= 168 hours a week.
Convert the problem to an equation using the percentage formula: P% * X = Y.
Let's take the 40% that is Sleep and use it in the percentage formula with the 168 hours.
40%x168= roughly 67 hours.
Hope this helped!
$25.50
15% of 30 is 4.5 which if you subtract it'll make $25.50 <span />
Its very hard to memorise them but if you practice and keep practicing you might get the hang of them. But heres a little trick alright? For the 11ths tables every except 12 will be 11,22,33 etc.. for instance 5 times 11 equals 55 or 8 times 11 equals 88.
