A past survey of 1, 068,000 students taking a standardized test revealed that 8.9% of the students were planning on studying engineering in college.
In a recent survey of 1, 476,000 students taking the SAT. 9.2% of the students were planning to study engineering.
Construct a 95% confidence interval for the difference between proportions ^p1−^p2 by using the following inequality. Assume the samples are random and independent.
(^p1−^p2)−zc√^p1^q1n1+^p2^q2n2 The confidence interval is _____

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Complete Question

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Answer:

The interval is  [tex]-0.0037 < p_1-p_2<-0.0023[/tex]

Step-by-step explanation:

From the question we are told that

   The first  sample size is  [tex]n _1 = 1068000[/tex]

    The  first sample proportion is [tex]\r p_1 = 0.089[/tex]

    The  second sample  size is  [tex]n_2 = 1476000[/tex]

    The  second sample proportion is  [tex]\r p_2 = 0.092[/tex]

   

Given that the confidence level is  95% then the level of significance is mathematically evaluated as

             [tex]\alpha = (100 - 95 )\%[/tex]

              [tex]\alpha = 0.05[/tex]

Next we obtain the critical value  of  [tex]\frac{\alpha }{2}[/tex]  from the normal distribution table  

The value is  

               [tex]Z_{\frac{\alpha }{2} } =z_c= 1.96[/tex]

Generally the 95% confidence interval is mathematically represented as

       [tex](\r p_1 - \r p_2 ) -z_c \sqrt{ \frac{\r p_1 \r q_1 }{n_1} + \frac{\r p_2 \r q_2 }{n_2}} < (p_1 - p_2 ) < (\r p_1 - \r p_2 ) +z_c \sqrt{ \frac{\r p_1 \r q_1 }{n_1} + \frac{\r p_2 \r q_2 }{n_2}}[/tex]

Here  [tex]\r q_1[/tex] is mathematically evaluated as [tex]\r q_1 = (1 - \r p_1)= 1-0.089 =0.911[/tex]

and  [tex]\r q_2[/tex]  is mathematically evaluated as  [tex]\r q_2 = (1 - \r p_2) = 1- 0.092 = 0.908[/tex]

So

       [tex](0.089 - 0.092 ) -1.96 \sqrt{ \frac{0.089* 0.911 }{1068000} + \frac{0.092* 0.908 }{1476000}} < (p_1 - p_2 ) < (0.089 - 0.092 ) +1.96 \sqrt{ \frac{0.089* 0.911 }{1068000} + \frac{0.092* 0.908 }{1476000}}[/tex]

[tex]-0.0037 < p_1-p_2<-0.0023[/tex]

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