Question

10) You have three coins one of which is biased so that it turns up tails 70% of the time. If 10) you randomly select one of the coins, tossed it three times, and obtained three tails what is the probability that this is the biased coin? A) 0.333 B) 0.578 C) 0.343 D) 0.622 11) Given that the confidence level is x%, give an expression in terms of x fora. C) 100-(1x)D)1. 10 A) B)100-Х 100 12) The daily revenue of a computer shop bas mean $7200 and standard deviation S1200. 12) The daily revenue will be monitored for the next 30 days. What is the probability that the mean daily revenue for the next 30 days will be between $7000 and $7500? C) 0.7333 D) 0.8186 A) 0.9147 B) 0.2667

Answer 1

Solution11:

alpha=1-confidence level

=1-x/100

MARK OPTION D

ANSWER:

OPTION D

Solution2:

mean=xbar=7200

sd=s=1200/sqrt(30)

=219.089

P(7000<xbar<7500)

use Rcode:

library(tigerstats)
pnormGC(c(7000,7500),region="between",mean=7200,sd=219.089,graph=TRUE)

output:

0.7338931

Normal Curve, mean 7200, SD 219.09 Shaded Area 0.7339 赜》 酱3 酱3 笔3 7500 7000

ANSWER:

OPTION C

0.7333