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math work............?
A university found that 30% of its students withdraw without completing the introductory statistics course. Assume that 20 students registered for the course.
Compute the probability that two or fewer will withdraw (to 4 decimals).
Compute the probability that exactly four will withdraw (to 4 decimals).
Compute the probability that more than three will withdraw (to 4 decimals).
Compute the expected number of withdrawals.
1 Answer
- M3Lv 710 years agoFavorite Answer
binomial distribution
0 C(20,0) * 0.3^0 * 0.7^20 0.00080
1 C(20,1) * 0.3^1 * 0.7^19 0.00684
2 C(20,2) * 0.3^2 * 0.7^18 0.02785
3 C(20,3) * 0.3^3 * 0.7^17 0.07160
4 C(20,4) * 0.3^4 * 0.7^16 0.13042
for the 1st 3 parts, extract data from the table & round to 4 dp
for P[>3], use its equivalent, 1 -P[≤3]
E[x] = np = 20*0.3 = 6 <--------
