That's a binomial probability problem with n=7 trials, p = 1/4,
and x=0 OR x=1

There are two ways, by formula or by graphing calculator.

By formula first (the long way):



Using x=0











Using x=1















Use the fact that OR means to ADD







By graphing calculator, if you have a TI-83 or TI-84,

Press 2ND VARS
Scroll to binomcdf(
Press ENTER

You may or may not see the next screen, depending of
the age of your calculator or the settings in MODE
If you see this screen, make it read this way:

                binomcdf
         trials:7
         p:1/4
         x value:1
         Paste

If you have that screen, scroll to 'Paste' and press ENTER

Whether you have that screen or not you should have this on
your main screen, whether you have to type it in or it's
already there:

binomcdf(7,1/4,1)

Press ENTER

Read    .4449462884

Edwin