Answer:
The estimate is
[tex]52.02 < \mu < 55.78[/tex]
Step-by-step explanation:
From the question we are told that
The sample mean is [tex]\ = x = 53.9[/tex]
The sample size is n = 24
The standard deviation is [tex]\sigma = 5.6[/tex]
Given that the confidence level is 90% the level of significance is mathematically represented as
[tex]\alpha = 100 - 90[/tex]
[tex]\alpha = 10 \%[/tex]
[tex]\alpha = 0.10[/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_{\frac{0.10 }{2} } = 1.645[/tex]
The reason we are obtaining critical value of [tex]\frac{\alpha }{2}[/tex] instead of [tex]\alpha[/tex] is because [tex]\alpha[/tex]
represents the area under the normal curve where the confidence level interval ( [tex]1 - \alpha[/tex] ) did not cover which include both the left and right tail while
[tex]\frac{\alpha }{2}[/tex] is just the area of one tail which what we required to calculate the margin of error
NOTE: We can also obtain the value using critical value calculator (math dot armstrong dot edu)
Generally the margin of error is mathematically represented as
[tex]E = Z_{\frac{\alpha }{2} } * \frac{\sigma }{ \sqrt{n} }[/tex]
substituting values
[tex]E = 1.645 * \frac{5.6 }{ \sqrt{24} }[/tex]
[tex]E = 1.880[/tex]
The estimate of how much the drug will lower a typical patient's systolic blood pressure(using a 90% confidence level) is mathematically represented as
[tex]\= x - E < \mu < \= x + E[/tex]
substituting values
[tex]53.9 - 1.880 < \mu < 53.9 + 1.880[/tex]
[tex]52.02 < \mu < 55.78[/tex]
