Answer:
To answer this question, you need to makes the unit of the smartphone screen same. In this case, phone A is using decimal and phone B is using a fraction. You can use which was easier.
Let's try to use decimal. Then you need to convert phone B fraction width into decimal width. The calculation would be: 5cm + 1/3cm= 5 cm + 0.333cm= 5.333cm
From here it clear that phone B has a wider screen than phone A.
Step-by-step explanation:
Answer:
Decreasing the sample size decreases the width of the confidence interval.
Step-by-step explanation:
-Let s be the sample standard deviation and
be the sample mean.
#We calculate the 95% confidence interval for the sample size 100 as below:

#we then calculate the confidence interval of sample size =50 and of similar mean and standard deviation:

#Notice that the smaller sample(n=50) has a narrower confidence interval.
Hence, decreasing the sample size decreases the width of the confidence interval.
Answer:
The correct option is:
A. We are 95% confident that the interval from 55.4 seconds to 61.2 seconds actually does contain the true value of μ.
Explanation:
In statistics, confidence interval is the interval estimate about the population parameter of interest at certain level of confidence like 95%. A 95% confidence interval gives us a range of values that we can be 95% confident contains the true mean of the population.
Therefore, the option A is correct