A school has two kindergarten classes. There are 21 children in Ms. Toodle's kindergarten class. Of these, 17 are "pre-readers" children on the verge of reading. There are 19 children in Mr. Grimace's kindergarten class. Of these, 13 are pre-readers. Using the plus four confidence interval method, a 90% confidence interval for the difference in proportions of children in these classes that are pre-readers is â0.104 to 0.336.

Which of the following statements is correct?

A) This confidence interval is not reliable because the samples are so small.
B)This confidence interval is of no use because it contains 0, the value of no difference between classes.
C)This confidence interval is reasonable because the sample sizes are both at least 5.
D) This confidence interval is not reliable because these samples cannot be viewed as simple random samples taken from a larger population.

Answer : D

Step-by-step explanation:

A school has two kindergarten classes. There are 21 children in Ms. Toodle's kindergarten class. Of these, 17 are "pre-readers" children on the verge of reading. There are 19 children in Mr. Grimace's kindergarten class. Of these, 13 are pre-readers. Using the plus four confidence interval method, a 90% confidence interval for the difference in proportions of children in these classes that are pre-readers is â0.104 to 0.336.  

Which of the following statements is correct?

A) This confidence interval is not reliable because the samples are so small.  

B)This confidence interval is of no use because it contains 0, the value of no difference between classes.  

C)This confidence interval is reasonable because the sample sizes are both at least 5.  

D) This confidence interval is not reliable because these samples cannot be viewed as simple random samples taken from a larger population.

The Answer is D - This confidence interval is not reliable because these samples cannot be viewed as simple random samples taken from a larger population.

In this setup, all the students are already involved in the data. This is not a sample from a larger population, but probably, the population itself.

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step-by-step explanation:

hope it you

step-by-step explanation:

sin(7pi/6 - pi/3)  

= sin(7pi/6 - 2pi/6)  

= sin(5pi/6)  

= sin(pi - pi/6)  

= sin(pi/6)  

= 1/2  

sin 7pi/6 - sin pi/3  

= sin (pi + pi/6) - sin pi/3  

= -sin pi/6 - sin pi/3  

= -1/2 - sqrt(3)/2  

= -(1+sqrt(3))2