Merry and bright? A string of Christmas lights con-
1 answer:
Answer:
0.6676
Step-by-step explanation:
given that A string of Christmas lights con-
tains 20 lights. The lights are wired in series, so that
if any light fails, the whole string will go dark. Each
light has probability 0.98 of working for a 3-year
period.
Each light is independent of the other.
The probability that the string of lights will
remain bright for 3 years.
= Probability that each light does not fail
= multiplication (prob of one light does not fail)
=
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Complete Question
The complete question is shown on the first uploaded image
Answer:
Yes the students are reasonably good at estimating one minute
a
Option A is correct
b
The test statistics is
Step-by-step explanation:
From the question we are told that
The set of data is
68, 82 , 38 , 62 , 41, 25 , 57 , 64, 67, 47, 61, 71, 91, 87, 64
The population mean is
The level of significance is given as
The critical value for this level of significance obtained from the normal distribution table is
The null hypothesis is
The alternative hypothesis is
Generally the sample mean is mathematically represented as
where n = 15
So
The standard deviation is mathematically represented as
substituting values
=>
The test statistics is evaluated as
substituting values
Now comparing the statistics and the critical value of the level of significance we see that the the test statistics is less than the critical value
Hence the we fail to reject the null hypothesis which mean that these times are from a population with a mean equal to 60 seconds
So we can state that yes the students are reasonably good at estimating one minute given that the sample mean is not far from the population mean
