Answer:
-0.0081<p<0.4081
Step-by-step explanation:
Using the formula for calculating the confidence interval expressed as;
CI = p±z√p(1-p)/n
p is the proportion = x/n
n is the sample size
x is the amount that are left-handed
p = 2/10
p = 0.2
z is the z score at 90% CI = 1.645
Substitute the values into the formula;
CI = 0.2±1.645√0.2(1-0.2)/10
CI = 0.2±1.645√0.2(0.8)/10
CI = 0.2±1.645√0.16/10
CI = 0.2±1.645√0.016
CI = 0.2±(1.645*0.1264)
CI = 0.2±0.2081
CI = (0.2-0.2081, 0.2+0.2081)
CI = (-0.0081, 0.4081)
hence the 90% confidence interval for the population proportion, p is expressed as -0.0081<p<0.4081
