A producer of mobile phones claims that 20% of all mobile phone users prefer its product. To test the claim, a random sample of 151 mobile phone users is selected and it turns out that 28 prefer the...

A producer of mobile phones claims that 20% of all mobile phone users prefer its product. To test the claim, a random sample of
151
mobile phone users is selected and it turns out that
28
prefer the producer’s brand. Do the data provide sufficient evidence that the production of mobile phone users who prefer the producer’s brand is less than 0.20? Test, using ? = 0.01.