Given that in a poll taken in December 2012, Gallup asked 1006 national adults whether they were baseball fans: 48% said they were. Almost five years earlier, in February 2008, only 35% of a similar-size sample had reported being baseball fans.

a) p is the proportion of national adults who are baseball fans.

b) For 2012 poll, p=0.48

Std error = $\sqrt{\frac{pq}{n} } \\=\sqrt{\frac{0.48*0.52}{1006} } \\=0.0158$

Margin of error at 90% = 1.645 * std error

= 0.0259

c) Margin of error is the admissible limit on either side of the mean where the sample mean can lie

d) Margin of error would be larger for 99% because critical value 2.58 >1.645

e) Margin of error 99% = $2.58*0.0157\\=0.0406$

6 0

4 years ago

How can I set each side equal to each other?

jekas [21]

RTP: [a tan(u) + b]² + [b tan(u) - a]² = (a² + b²) sec²(u)

Proving LHS = RHS:

LHS = [a tan(u) + b]² + [b tan(u) - a]²

= a² tan²(u) + 2ab tan(u) + b² + b² tan²(u) - 2ab tan(u) + a²
= (a² + b²) tan²(u) + (a² + b²)
= (a² + b²)[tan²(u) + 1]
= (a² + b²) sec²(u), using the identity: tan²(x) + 1 = sec²(x)
= RHS

7 0

3 years ago