In an article in marketing science, silk and berndt investigate the output of advertising agencies. they describe ad agency output by finding the shares of dollar billing volume coming from various media categories such as network television, spot television, newspapers, radio, and so forth. suppose that a random sample of 392 u. s. advertising agencies gives an average percentage share of billing volume from network television equal to 7.41 percent, and assume that alpha equals 1.43 percent. calculate a 95 percent confidence interval for the mean percentage share of billing volume from network television for the population of all u. s. advertising agencies.

(7.27%, 7.55%)

Step-by-step explanation:

As per given , we have

Sample size : n= 392

Sample mean :

Critical two-tailed z-value for 95% confidence =

Required confidence interval would be :

Hence, the required 95% confidence interval for the mean percentage share of billing volume from network television for the population of all U.S. advertising agencies : (7.27%, 7.55%)

answer: 204

step-by-step explanation:

we are told that the revenue is

x⋅(4080−10x)=−10x^2+4080x

this is a quadratic function, so to maximize it we should find the x-value of its vertex. recall that the x-value of the vertex of the parabola ax^2+bx+c is given by the formula −b/2a.

so in this case, we have a=−10 and b=4080, so the x-value of the vertex is

−b/2a= −(4080)/2(−10)=204

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step-by-step explanation: