Example 5
The record of a weather station shows that out of the past 250 consecutive days, its weather forecasts were correct 175 times.
(i) What is the probability that on a given day it was correct?
The total number of days for which the record is available = 250
Number of days when forecast was correct = 175
P(the forecast was correct on a given day)
= (ππ’ππππ ππ πππ¦π πππ π€βππ πππππππ π‘ π€ππ πππππππ‘)/(πππ‘ππ ππ’ππππ ππ πππ¦π πππ π€βππβ π‘βπ ππππππ ππ ππ£πππππππ)
= 175/250
= 0.7
Example 5 (Method 1)
The record of a weather station shows that out of the past 250 consecutive days, its weather forecasts were correct 175 times.
(ii) What is the probability that it was not correct on a given day?
The total number of days for which the record is available = 250
The number of days when the forecast was not correct = 250 β 175
= 75
P(the forecast was not correct on a given day)
= (ππ’ππππ ππ πππ¦π πππ π€βππ πππππππ π‘ π€ππ πππ‘ πππππππ‘)/(πππ‘ππ ππ’ππππ ππ πππ¦π πππ π€βππβ π‘βπ ππππππ ππ ππ£πππππππ)
= 75/250
= 0.3
Example 5 (Method 2)
The record of a weather station shows that out of the past 250 consecutive days, its weather forecasts were correct 175 times.
(ii) What is the probability that it was not correct on a given day?
P(the forecast was not correct on a given day)
= 1 β P(forecast was correct on a given day)
= 1 β 0.7
= 0.3

Made by

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths and Science at Teachoo.