document.write( "Question 1101231: During the past forty years, the monthly rate of return of stocks has been approximately normally \n" );
document.write( "distributed, with µ = 0.75 percent and σ = 4.2 percent, according to data obtained from \n" );
document.write( "Yahoo!Finance. \n" );
document.write( "(i) What is the probability that a randomly selected month has a rate of return of at least 1 \n" );
document.write( "percent? \n" );
document.write( "(ii) What is the probability that a randomly selected month has a rate of return less than 2 percent? \n" );
document.write( "(iii) What proportion of months have a positive rate of return? \n" );
document.write( "(b) According to the Energy Information Administration, 42.1% of households in the United States \n" );
document.write( "owned a personal computer in 1998. An economist wants to discover whether this percentage has \n" );
document.write( "changed significantly since then. She randomly selects 320 households throughout the United States \n" );
document.write( "and finds that 154 of them own a personal computer. Is there sufficient evidence to conclude the \n" );
document.write( "percentage of households that own a personal computer is significantly different from the percentage \n" );
document.write( "in 1998, at the α = 0.01 level of significanc \n" );
document.write( "
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