The confidence interval for a <span>(1−α)%</span> confidence level is given by
<span>
(<span>θ0</span>−<span>Z<span>α/2 </span></span><span>σ/√n</span>, <span>θ0</span>+<span>Z<span>α/2 </span></span><span>σ/√n</span>)
</span><span>θ0</span> is the measured statistic, <span>Z<span>α/2</span></span> is the cutoff/critical value, and <span>σ/<span>√n</span></span> is the standard error. σ is the population standard deviation (if known) or can be estimated by a sample standard deviation. n is the sample size.
The cutoff value depends on the test you wish to use, and <span>θ0</span><span> depends on the statistic you wish to estimate.</span>
Answer:
(a) The probability that a single randomly selected value lies between 158.6 and 159.2 is 0.004.
(b) The probability that a sample mean is between 158.6 and 159.2 is 0.0411.
Step-by-step explanation:
Let the random variable <em>X</em> follow a Normal distribution with parameters <em>μ</em> = 155.4 and <em>σ</em> = 49.5.
(a)
Compute the probability that a single randomly selected value lies between 158.6 and 159.2 as follows:

*Use a standard normal table.
Thus, the probability that a single randomly selected value lies between 158.6 and 159.2 is 0.004.
(b)
A sample of <em>n</em> = 246 is selected.
Compute the probability that a sample mean is between 158.6 and 159.2 as follows:

*Use a standard normal table.
Thus, the probability that a sample mean is between 158.6 and 159.2 is 0.0411.
Answer:
Total no. of houses = 140
Step-by-step explanation:
Let there are 9x flats and 5x bungalows.
Total bungalows = 50
It means,
5x = 50
x = 10
No of flats = 9x
= 9(10)
= 90
Total houses = no. of flats + no. of bungalows
= 50+90
= 140
So, there are 140 houses in the village.