A local weather forecaster is accurate 85% of the time when predicting precipitation for the day. What is the probability that she will make correct precipitation predictions 4 days in a row?
about 54%
about 53%
about 52%
about 47%

Question

A local weather forecaster is accurate 85% of the time when predicting precipitation for the day. What is the probability that she will make correct precipitation predictions 4 days in a row?
about 54%
about 53%
about 52%
about 47%

kropot72 · Answer

The probability of being correct on one day is 0.85. The forecast for each day is separate and independent of the other daily forecasts. Therefore the compound event, correct predictions 4 days in a row, is the product of the separate probabilities of being correct for each of the 4 days.
P(correct 4 days) = 0.85 * 0.85 * 0.85 * 0.85.

Can you calculate the probability and convert to a percentage ?

wolfboy · Answer

ehh i might need some help with that

kropot72 · Answer

Have you got a calculator handy?

wolfboy · Answer

Yus

wolfboy · Answer

*yes

kropot72 · Answer

Multiply 0.85 by 0.85. Then multiply the answer by 0.85. Then multiply that answer by 0.85. What do you get?

wolfboy · Answer

.52200625

kropot72 · Answer

Correct. To convert to a percentage multiply 0.52200625 by 100. Then choose the answer that is closest to the result.

wolfboy · Answer

Tank you lots!

kropot72 · Answer

You're welcome :)