document.write( "Question 271204: To test the null hypothesis that the average lifetime for a particular brand of bulb is 750 hours versus the alternative that the average lifetime is different from 750 hours, a sample of 75 bulbs is used. If the standard deviation is 50 hours and a is equal to 0.01, what values for will result in rejection of the null hypothesis. Remember to determine whether this is a one- or two-tailed test. (Hint: This is similar to problem #4 but it is NOT a one-tailed test!) \n" ); document.write( "
Algebra.Com's Answer #198831 by stanbon(75887)\"\" \"About 
You can put this solution on YOUR website!
To test the null hypothesis that the average lifetime for a particular brand of bulb is 750 hours versus the alternative that the average lifetime is different from 750 hours, a sample of 75 bulbs is used.
\n" ); document.write( "If the standard deviation is 50 hours and a is equal to 0.01, what values for will result in rejection of the null hypothesis. Remember to determine whether this is a one- or two-tailed test.
\n" ); document.write( "======
\n" ); document.write( "Ho: u = 750
\n" ); document.write( "Ha: u is not equal to 750 (2-tail test)
\n" ); document.write( "------------------------
\n" ); document.write( "Critical values for 2-tail, with alpha = 1% and df = 74:
\n" ); document.write( "Using a TI-84 calculator I get invT(0.005,74) = +-2.6439
\n" ); document.write( "---
\n" ); document.write( "The rejection intervals are t<-2.6439 and t>2.6439
\n" ); document.write( "==============
\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H. \n" ); document.write( "
\n" );