a) See attached diagram.
b) The slope can be obtained by the formula:
Now
The greatest increases were from 2012 till 2013 years and the least increases were from 2007 till 2008 years.
c) Using graphing calculator, the equation of the line (black line in the diagram) is
d) Since the slopes are different, this line is not straight. From the given data you can predict that the "best fit" is quadratic function.
e) In 2017, find
Answer:
The margin of error is approximately 0.3
Step-by-step explanation:
The following information has been provided;
The sample size, n =225 students
The sample mean number of hours spent studying per week = 20.6
The standard deviation = 2.7
The question requires us to determine the margin of error that would be associated with a 90% confidence level. In constructing confidence intervals of the population mean, the margin of error is defined as;
The product of the associated z-score and the standard error of the sample mean. The standard error of the sample mean is calculated as;
where sigma is the standard deviation and n the sample size. The z-score associated with a 90% confidence level, from the given table, is 1.645.
The margin of error is thus;
Therefore, the margin of error is approximately 0.3