17. How
many
survey
responses
do
you
need
if
you
have
10,000
customers?
How
many
email
opens
do
you
need
to
test
2
subject
lines
if
your
subscriber
base
is
50,000?
How
many
orders
do
you
need
to
test
6
banner
execu-ons
if
you
serve
1,000,000
banners
Google
“nss
sample
size
calculator”
18. How
many
survey
responses
do
you
need
if
you
have
10,000
customers?
369
for
each
ques-on
or
369
complete
responses
How
many
email
opens
do
you
need
to
test
2
subject
lines
if
your
subscriber
base
is
50,000?
And
email
sends?
381
per
subject
line
or
381
x
2
=
762
email
opens
How
many
orders
do
you
need
to
test
6
banner
execu-ons
if
you
serve
1,000,000
banners?
383
sales
per
banner
execu-on
or
383
x
6
=
2,298
sales
Google
“nss
sample
size
calculator”