var arraystring = ['test', 'cat', 'meow'];
checkEarraystring(arraystring);

function checkEarraystring (arraystring){
    var letter = "e";
    var arr = [];
    for (var i=0; i<arraystring.length;i++) {
            arr[i] = arraystring[i]>= letter;
    }
    return arr
}
alert(checkEarraystring(arraystring))