Two friends, Karen and Jodi, work different shifts for the same ambulance service. They wonder if the different shifts average different numbers of calls. Looking at past records, Karen determines from a random sample of 37 shifts that she had a mean of 4.5 calls per shift. She knows that the population standard deviation for her shift is 1.1 calls. Jodi calculates from a random sample of 32 shifts that her mean was 5.3 calls per shift. She knows that the population standard deviation for her shift is 1.5 calls. Test the claim that there is a difference between the mean numbers of calls for the two shifts at the 0.05 level of significance. Let Karen's shifts be Population 1 and let Jodi's shifts be Population 2. Step 2 of 3 : Compute the value of the test statistic. Round your answer to two decimal places

Respuesta :

The Test value for difference between the mean numbers of calls for the two shifts at the 0.05 level of significance is 31.94

According to the question,

Karen's data:

Sample size : n₁ = 37

Sample mean = 4.5

Sample standard deviation : s₁ = 1.1

Jodi's data ,

Sample size : n₂ = 32

Sample mean = 5.3

Sample standard deviation : s₂ = 1.5

To calculate significance difference between two means we use t-test

t = difference of mean / √(pooled variance / n₁ + n₂)

Pooled Standard deviation = [tex]\sqrt(\frac{(n_1 - 1)s_1^{2} + (n_2 - 1)s_2^{2})}{n_1 + n_2 -2}[/tex]

=> [tex]\sqrt(\frac{(37 - 1)1.21+ (32 - 1)2.25)}{37 + 32 -2}[/tex]

=> [tex]\sqrt(\frac{(43.56+ 69.75)}{67}[/tex]

=>[tex]\sqrt(\frac{(113.31)}{67}[/tex]

=> √1.6911

t = 37 - 32 / (√1.6911/37+32)

=> 5 / √0.0245

=> 31.94  is test value

To know more about Test statistic here

https://brainly.com/question/14128303

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