Answer:
CI =(0.333, 0.480)
Step-by-step explanation:
The formula for calculating the confidence interval is expressed as shown;
CI = p±Z * √p(1-p)/n±0.5/n
Z is the z-score at 90% confidence
p is the sample proportion
n is the sample size
Given n = 144, p = 0.4 and z-score at 90% CI = 1.645 (from z table)
Substituting this values;
CI = p ± 1.645*√0.4(1-0.4)/144 ±0.5/n
CI = 0.4 ± 1.645*√0.4(0.6)/144 ± 0.5/144
CI = 0.4 ±1.645 * √0.24/144 ± 0.00347
CI = 0.4 ±1.645 * 0.04087± 0.00347
CI = 0.4±0.06723±0.00347
CI =(0.333, 0.480)
Answer:
the mean marks of the girls is 86%
Step-by-step explanation:
She paid 11 dollars total
Step-by-step explanation:
100% of $5 is $10
10% of $10 is $1
10 + 1 = 11
Hmm, this is a tricky one. I'll do my best, though.
Well, we know that __ + __ = 36 and that one of the 2 numbers is double the other. We'll use x to be one number, and we'll use 2x to be double the number (because when you double x, you'll have 2x). And we know that we add them, right?
x + 2x = 36. Now this is making sense! Just solve it!
x+2x=36
3x=36
x=12 But don't forget, that's only the age of the younger sister. The older sister is double the age of x, or 12. What is 12 doubled? 24.
<em>The age of the two sisters is</em><em> 12 </em><em>&</em><em> 24</em><em>.</em>
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