I need help with a HW assigment in R code. write an R code to read the file and calculate the mean of heights. Remember to remove those entries with no height entered.

below is data from an excel file. Please Help.

sex	height	weight	handedness	exercise	smoke
Female	68	158	Right	Some	Never
Male	70	256	Left	None	Regul
Male	NA	204	Right	None	Occas
Male	63	187	Right	None	Never
Male	65	168	Right	Some	Never
Female	68	172	Right	Some	Never
Male	72	160	Right	Freq	Never
Female	62	116	Right	Freq	Never
Male	69	262	Right	Some	Never
Male	66	189	Right	Some	Never
Female	62	145	Right	Freq	Never
Male	NA	210	Right	Freq	Never
Female	61	169	Right	Some	Never
Female	61	142	Right	Some	Never
Male	NA	152	Right	Some	Never
Female	61	144	Right	Freq	Never
Female	62	130	Right	Freq	Never
Male	72	179	Left	Some	Never
Male	75	226	Right	Some	Never
Male	70	193	Right	Freq	Never
Male	75	182	Right	Freq	Never
Male	71	149	Right	Freq	Never
Male	71	180	Right	Freq	Never
Male	72	204	Right	Some	Never
Female	NA	132	Right	Some	Never
Male	NA	242	Right	Some	Never
Male	68	208	Right	Some	Never
Male	69	171	Right	Freq	Never
Male	NA	137	Right	Freq	Never
Male	66	215	Right	Some	Never
Female	NA	152	Right	None	Occas
Male	71	211	Right	Freq	Never
Female	66	136	Right	Freq	Heavy
Male	71	232	Right	Some	Never
Male	NA	260	Right	Some	Regul
Male	75	179	Right	Freq	Occas
Female	66	172	Right	Some	Never
Male	72	218	Right	Freq	Never
Male	73	213	Right	Some	Never
Male	67	191	Right	Freq	Occas
Female	66	137	Right	Some	Never
Female	61	161	Right	Some	Never
Male	68	189	Right	Some	Never
Female	70	138	Right	Some	Never
Female	71	172	NA	Freq	Never
Male	71	228	Right	Freq	Never
Male	71	215	Right	Freq	Regul
Male	67	148	Right	None	Never
Female	66	162	Right	Some	Occas
Female	65	183	Right	None	Never
Male	79	173	Left	Freq	Never
Male	75	224	Right	Freq	Never
Male	67	204	Right	Some	Never
Male	70	195	Right	Freq	Never
Male	72	181	Right	Freq	Regul
Male	67	157	Right	Freq	Never
Female	62	197	Right	None	Never
Male	NA	195	Right	Freq	Never
Male	70	194	Right	Freq	Never
Male	69	186	Left	Freq	Occas
Male	74	167	Right	Freq	Never
Female	66	141	Right	Freq	Never
Female	70	122	Right	Freq	Never
Female	67	169	Left	None	Never
Female	65	185	Right	Freq	Never
Male	72	197	Right	Freq	Never
Female	68	152	Right	Freq	Never
Female	NA	175	Right	Freq	Never
Male	71	183	Right	Some	Never
Male	NA	238	Right	None	NA
Female	67	102	Right	Freq	Never
Male	69	197	Right	Freq	Heavy
Female	67	159	Right	Some	Never
Female	66	141	Right	Freq	Never
Female	65	157	Right	Some	Never
Female	67	176	Right	Freq	Heavy
Female	65	172	Right	Some	Never
Female	65	151	Right	Freq	Heavy
Female	65	155	Right	Some	Never
Male	73	174	Right	Freq	Never
Male	NA	189	Left	Some	Never
Male	70	168	Right	Freq	Never
Female	NA	105	Right	Freq	Never
Female	NA	156	Right	Some	Never
Male	66	213	Right	Freq	Never
Female	66	156	Right	Some	Never
Female	64	169	Right	Some	Never
Female	67	171	Right	Freq	Never
Male	70	186	Right	Freq	Never
Female	NA	119	Left	Some	Never
Male	72	164	Right	Some	Never
Female	NA	141	Right	Some	Never
Female	65	134	Right	Some	Never
Female	66	166	Right	Some	Never
Male	70	185	Right	Freq	Heavy
Female	NA	159	Right	Some	Never
Male	75	177	Right	Freq	Regul
Female	66	150	Right	Freq	Never
Male	65	199	Right	Freq	Never
Female	69	82	Right	Freq	Never
Male	74	178	Right	Some	Never
Male	67	237	Right	None	Never
Female	63	157	Right	Some	Never
Female	69	131	Right	Freq	Never
Female	64	141	Right	Some	Heavy
Female	67	121	Right	Some	Never
Female	68	148	Right	Freq	Occas
Female	NA	178	Right	Freq	Never
Male	71	166	Right	Freq	Never
Male	71	240	Right	Some	Regul
Female	69	138	Right	Freq	Never
Male	75	165	Right	None	Never
Female	67	129	Right	Freq	Never
Male	73	157	Right	Freq	Never
Female	64	98	Right	Freq	Never
Female	62	164	Right	None	Never
Female	63	180	Right	Some	Never
Male	76	137	Left	Some	Heavy
Female	67	203	Left	Some	Never
Male	72	163	Right	Freq	Heavy
Male	NA	193	Right	Freq	Occas
Male	70	174	Right	Freq	Occas
Female	68	157	Right	Freq	Never
Male	71	170	Left	Freq	Never
Male	69	199	Right	Freq	Never
Male	71	185	Right	Freq	Never
Female	68	103	Right	Freq	Never
Male	70	190	Right	Freq	Regul
Female	62	166	Right	Freq	Never
Female	60	157	Right	Some	Never
Male	74	166	Right	Freq	Never
Male	70	155	Right	Some	Never
Female	NA	181	Right	Some	Never
Female	63	129	Left	Freq	Occas
Male	69	220	Right	Some	Never
Male	74	192	Right	Some	Regul
NA	68	0	Left	Freq	Never
Male	72	177	Right	Freq	Never
Male	67	217	Right	Freq	Never
Female	66	189	Right	None	Never
Female	69	157	Right	Some	Never
Female	65	136	Right	None	Never
Female	68	159	Right	Freq	Never
Male	71	150	Right	Some	Never
Female	68	86	Left	Freq	Never
Male	73	187	Right	Some	Never
Male	74	203	Right	Freq	Regul
Male	73	171	Right	Freq	Never
Female	65	162	Right	Freq	Never
Female	65	156	Right	Freq	Never
Male	77	191	Right	Freq	Never
Female	65	180	Right	Freq	Never
Female	60	158	Right	Some	Regul
Male	68	200	Right	Freq	Never
Male	71	233	Right	None	Never
Male	68	162	Right	Freq	Never
Male	NA	191	Right	Freq	Heavy
Female	66	126	Right	Some	Never
Male	74	228	Right	None	Never
Male	74	199	Right	Freq	Regul
Female	66	177	Right	None	Never
Male	66	170	Left	Some	Never
Male	76	237	Right	Some	Never
Female	67	99	Right	Freq	Occas
Male	70	241	Right	Some	Never
Female	66	164	Right	Some	Never
Female	67	152	Right	Some	Never
Female	63	157	Right	Some	Regul
Male	74	168	Right	Freq	Never
Male	71	210	Right	Freq	Never
Female	66	167	Right	Some	Never
Male	72	215	Left	Some	Occas
Female	NA	134	Right	Some	Regul
Female	65	170	Right	Freq	Never
Female	62	151	Right	Freq	Never
Female	67	160	Left	Freq	Never
Male	68	189	Right	Freq	Regul
Female	65	181	Right	Freq	Never
Female	NA	184	Right	Freq	Regul
Female	64	132	Right	Some	Never
Male	68	186	Right	Freq	Occas
Female	65	112	Right	Freq	Occas
Female	64	128	Right	Some	Never
Male	67	156	Right	Freq	Never
Male	69	221	Right	Some	Never
Male	66	958	Right	Some	Never
Female	64	184	Right	Some	Never
Male	65	198	Right	None	Never
Male	68	183	Right	Freq	Never
Male	77	168	Right	Freq	Never
Male	70	221	Right	Some	Never
Male	71	150	Right	Some	Never
Male	69	185	Right	None	Occas
Female	63	150	Right	Some	Never
Female	62	159	Right	None	Never
Female	65	160	Right	Some	Never
Female	67	116	Right	Freq	Never
Male	61	175	Right	Freq	Never
Female	67	133	Right	Some	Occas
Female	65	147	Right	Some	Never
Female	66	154	Right	Some	Occas
Male	68	180	Right	Freq	Never
Female	NA	138	Right	Some	Never
Female	63	176	Right	None	Never
Male	70	242	Right	Some	Regul
Female	66	101	Right	Freq	Occas
Female	60	148	Right	Some	Never
Male	63	193	Right	Some	Never
Male	65	232	Left	None	Never
F	68	112	Right	Freq	Never
F	63	121	Right	Some	Never
F	64	108	Left	Some	Never
M	NA	178	Right	Freq	Never
M	65	197	Right	Some	Never
Female	66	192	Right	Some	Never
Male	67	145	Right	Some	Never
Female	NA	152	Right	None	Never
Male	73	150	Right	Freq	Never
Female	68	118	Right	Freq	Never
Male	74	177	Right	Freq	Never
Male	67	189	Right	None	Heavy
Female	66	141	Right	Freq	Never
Female	64	132	Right	Some	Never
Female	59	147	Right	Freq	Never
Female	NA	126	Right	Some	Never
Female	NA	139	Right	Some	Never
Female	67	178	Right	Some	Heavy
male	73	218	Right	Freq	Never
female	66	137	Right	Freq	Regul
Male	73	195	Right	Freq	Occas
Female	66	169	Right	Some	Never
Male	71	141	Right	Some	Never
Female	65	156	Right	Some	Never
Female	63	159	Right	Some	Never
female	67	152	Right	Some	Never
male	72	193	Right	Some	Never
female	66	178	Right	Freq	Never