Answer:
Option (B) is the correct answer to the following question.
Step-by-step explanation:
Step-1: We have to find the Mean of the series.
The series is Given in the question 62 61 61 57 61 54 59 58 59 69 60 67.

Step-2: We have to find the Standard Deviation.
Let Standard Deviation be x.
Formula of Standard Deviation is: 
Put value in formula of Standard Deviation,
= 40.75
Step-3: Then, we have to find the critical value by chi-square.


Then, find the confidence interval which is 95%.


Answer:
c
Step-by-step explanation:
45:15=3:1 not 1:3
Given:
The table of values is
Number of Students : 7 14 21 28
Number of Textbooks : 35 70 105 140
To find:
The rate of change and showing that the ratios of the two quantities are proportional and equivalent to the unit rate.
Solution:
The ratio of number of textbooks to number of students are




All the ratios of the two quantities are proportional and equivalent to the unit rate.
Let y be the number of textbooks and x be the number of students, then

Here, k=5.


Hence the rate of change is constant that is 5.
Answer:
189.875
Step-by-step explanation: